ABSTRACT/POSTER PRESENTATION Liposclerosing fibromyxoid ... Sprin… · Liposclerosing fibromyxoid tumour (LSFMT) is a rare, benign fibroosseous bone - tumour frequently detected

ABSTRACT/POSTER PRESENTATION Liposclerosing fibromyxoid tumour, a rare bone tumour of intertrochanteric region of femur Xiu Fen Chen, Sathiyamoorthy Selvarajan Department of Anatomical Pathology, Division of Pathology, Singapore General Hospital. Introduction Liposclerosing fibromyxoid tumour (LSFMT) is a rare, benign fibro-osseous bone tumour frequently detected at the intertrochanteric region of the femur with specific radiological features. It typically shows a constellation of histological features and was reported to have a minimal risk of malignant transformation. Here, we present a case of LSFMT located at the intertrochanteric area in an elderly man. Case report A 90-year-old man presented with a fall and suffered from a greater trochanteric fracture. Computed tomography of the left hip performed showed a well-defined intramedullary lucent lesion with sclerotic margins centred in the intertrochanteric region measuring 4.2cm. A left hip hemiarthroplasty was performed. The femoral head revealed a cystic lesion on gross examination. Histological sections displayed an intramedullary to subcortical lesion showing curvilinear and circular fragments of woven bones in a fibrous stroma. Distinct fragments of woven bone with irregular cement lines of calcification were featured resembled pseudo-pagetoid pattern. There were also intervening adipose tissue, foamy macrophages and cystic degeneration. The features described were those of a LSFMT. Differential diagnoses included fibrous dysplasia and intraosseous lipoma. The important feature that helped to differentiate LSFMT from its mimics was the presence of wide spectrum of histomorphology. Conclusion It is important to recognised LSFMT as this entity may sometimes generate a diagnostic challenge for pathologists. It should be included in the differential diagnosis when one encounters a fibro-osseous lesion with complex mixture of histological pattern to prevent an erroneous diagnosis as other benign or malignant bone producing tumour.

HKIAP Spring Scientific Meeting 2019 Page 1

ABSTRACT/POSTER PRESENTATION Intraneural Granular Cell Tumor – Histologic Spectrum and Histogenetic Implication Maria Bernadette Che Ying Chow1 and Louis Tsun Cheung Chow2 1Department of Clinical. Pathology NDH; 2Department of Clinical. Pathology TMH. Granular cell tumor (GCT) is a benign tumor characterized by large polygonal cells with central nuclei and abundant eosinophilic granular appearing cytoplasm. It accounts for 0.5% of all soft tissue tumours, and is first described by Abrikossoff as myoblastoma due to its glossal location but later widely believed to be neural in origin. However, it is commonly found in the extraneural location including the skin and subcutis, tongue and breast, but only 6 single case reports of genuine intraneural GCT have been described. A 28-year-old female clerk complained of pain over left forearm, progressive weakness of left hand and fingers for 2 years, associated with swelling over the painful site for the recent 6 months. Examination revealed an ill-defined fusiform 3x4.5 cm tender mass in the proximal lateral aspect of left forearm. The excised oval well-circumscribed tumor 6 x 1.5 x1 cm showed a uniform yellow firm cut surface, located entirely within the posterior interosseous nerve epineurium. It consisted of small clusters and single isolates of benign polygonal tumor cells supported in a fibroblastic stroma. At both ends, the tumor cells displaced the nerve fibres to the periphery but in the center, they replaced most of the nerve fibres. The polygonal tumor cells possessed central nuclei and abundant granular eosinophilic cytoplasm staining positively for PASD and S100. Mitosis is less than 1/40 HPF. The patient remained well after 4.5 years. Our case stands out from all reported cases as the only one with motor dysfunction, longest duration of symptoms, largest tumor size with resultant muscle atrophy and fatty infiltration. In addition, the lack of significant contrast enhancement in the MRI arouses the suspicious that it is not peripheral nerve sheath tumor. The clinical and pathological features of the reported and our case of intraneural GCT are reviewed. They affect four females and three males, age ranging from 14 to 43 years. Apart from one involving the cervical dorsal nerve root, all others involve upper limb peripheral nerves. Four present with symptoms of sensory motor nerve compression including numbness, pain and tingling sensation, one with weakness due to motor


dysfunction, and two with subcutaneous nodules. Tinel’s sign is positive in those with sensory nerve GCT and the patient with dorsal nerve root lesion shows upper motor neurone signs due to its spinal location. The sizes of the tumor range from 6 to 45 mm, and the preoperative clinical diagnosis in all instances is peripheral nerve sheath tumor, ours with atypical features. Follow up information is available in five, all remain well with no local recurrence 10 to 54 months after surgical excision. The striking feature of intraneural GCT lies in the histopathologic variety, ranging from benign GCT, through plexiform, hybrid GCT and perineurioma to malignant GCT, encompassing the full spectrum of extraneural GCT. As the immunophenotypes of schwannoma and GCT are not exactly identical, together with evidence from ultrastructural studies, the more reasonable and likely possibility is that GCT originates from undifferentiated mesenchymal cells acquiring partial schwannian differentiation. Such postulation by virtue of the widespread occurrence of mesenchymal cells in the soft tissue, better explains the topographic distribution of GCT in extraneural and intraneural location.


ABSTRACT/POSTER PRESENTATION Prevalence of EGFR mutations in squamous cell lung carcinoma Ho-Kwan Cheung, Joanna Tong, Lau-Ying Chung, Shuk-Ling Chau, Ka-Fai To Department of Anatomical and Cellular Pathology, Prince of Wales Hospital, Hong Kong Whether EGFR mutations occur in squamous cell lung carcinoma (SCLC) remains a controversial issue. Previous studies had produced contrasting results, depending on the ethnicity of the recruited subjects, the nature of specimens being studied, and whether ancillary diagnostic studies had been used. Obviously, the confirmation or dismissal of EGFR mutations in SCLC, at least in our ethnicity, has major diagnostic and therapeutic implications. Investigating the prevalence of EGFR mutations in SCLC is not straightforward. In a small biopsy, it is impossible to conclude if the biopsy originates from a pure SCLC or from a part of an adenosquamous carcinoma. Adenocarcinoma can also at times mimic squamous carcinoma morphologically. Because EGFR mutations occur commonly in adenosquamous carcinoma and adenocarcinoma, presence of EGFR mutations in a tumour thought to be SCLC prompts careful exclusion of an occult glandular component. To characterize the prevalence of EGFR mutation in SCLC, we conducted a retrospective, observational study involving 191 excision specimens diagnosed to be SCLC from a consecutive cohort of patients in year 2000-2011. On representative blocks from all the excision specimens, we performed a panel of histochemical and immunohistochemical markers, including p40, p63, CK5/6, TTF-1, and mucicarmine, to ascertain the squamous differentiation of each case. Genomic DNA was extracted and the EGFR mutation status was determined by Cobas (Roche) assay. Of the 191 cases, 4 were found to harbour EGFR mutations. One case (with L858R mutation) was reclassified as adenosquamous carcinoma, and the remaining 3 cases (2 with L858R mutation, 1 with exon 19 deletion) showed typical squamous morphological features and immunohistochemical profile, i.e. positive for p40 and CK5/6, negative for TTF-1 and mucicarmine. Thus, we report that a small subset of rigourously proven SCLC is found to harbour EGFR mutations. The therapeutic implications of this finding remain to be further explored.


ABSTRACT/POSTER PRESENTATION Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia (DIPNECH)—Report of Two Cases Chih-Jung Chen1,2, Yi-Chen Yeh3, Mei-Ling Chen1, Shang-Yun Ho4,5 1Department of Surgical Pathology, Changhua Christian Hospital, Changhua, Taiwan 2School of Medicine, Chung Shan Medical University, Taichung, Taiwan 3Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan 4Department of Medical Imaging, Changhua Christian Hospital, Changhua, Taiwan 5Department of Medical Imaging and Radiological Science Chung-Shan Medical University, Taichung, Taiwan 1. Objectives Diffuse Idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare and poorly understood pulmonary disorder and first named by AGUAYO et al, 1992. Now DIPNECH is considered as a pre-neoplastic process by 2015 WHO classification. It is characterized by female predominant tendency, smoking history, accompanied with cough or exertional dyspnea consistent with obstructive or mixed obstructive/restrictive lung diseases. The computed tomography (CT) scan showed typically multiple bilateral pulmonary reticulo-nodulities diffusely. Without comprehensive clinical correlations, making a correct diagnosis is sometimes difficult and changeling. Herein, we introduced two DIPNECH cases characterized by multiple bilateral lung reticulonodules mimicking lung metastases and focused on the histological findings. 2. Clinical Presentation and Pathological Findings Case 1. A 66 y/o lady complained of cough for few days with productive sputum. Neither fever nor other infection symptom/sign was noted. Multiple bilateral lungs tiny nodules or reticular lesions were noted by CT scan. Left upper lung and left lower lung wedge resections were performed. Microscopically, there were multiple, scattered peri-bronchioloar neuroendocrine cells proliferations manifested as a morphological spectrum from linear cellular growth, intra-epithelial micro-nodules, tumorlet formation(diameter < 0.5 cm) and frank invasion lesions/tumors as typical carcinoid tumors. Immunohistochemically, neuroendocrine nature of tumor cells was confirmed by synaptophysin, chromogranin and CD56 immunostains. In addition, these tumor cells displayed TTF-1(+, focal and weak), ki67labeling index(<3%), p63(-), PR(-),


GATA3(-), PAX8(-) and S-100(-) these immunoprofiles made other possibilities such as paraganglioma or neuroendocrine tumors from other anatomic sites less likely. After clinical survey, no evidence of other primary site was confirmed. The post-operative course was uneventful during 8 months follow-up. Dexamethasone was prescribed and the disease now was stationary without progress and metastases. Case 2. 42 y/o lady, complained of cough for 3 months with exertional dyspnea. Neither fever nor other infection symptom/sign was noted. The CT scan showed similar image findings as “case 1”. Right upper lung and right middle lung wedge resections were done. Microscopically, diffusely similar neuroendocrine cell proliferations from linear cellular growth to typical carcinoid tumor as “case 1” in both lung lobes. The patient then accepted 5-FU chemotherapy. The post-operative course was uneventful about 8-year-followup and the disease now was stationary without progress. 3. Conclusion Pre-cancerous lesions of pulmonary NEN, such as DIPNECH, are quite rare and hard to detect clinically. Keep high suspicious and be aware of this rare entity clinically and histologically is important. In addition, exclusion the other mimickers such as non-neoplastic neuroendocrine hyperplasia caused by inflammation or infection is also crucial to render a correct diagnosis. Multi-planetary conference is necessary and recommended for making correct diagnoses and adequate patients’ managements. Keywords Diffuse Idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH); carcinoid


ABSTRACT/POSTER PRESENTATION Ghazala Sadaf Armed Forces Institute of Pathology, Pakistan 1. Objective: To evaluate immunohistochemical expression of PDL1 in non small cell lung cancer. 2. Methodology: Study design: Descriptive, Cross sectional study Place and Duration of Study: Histopathology department, Armed Forces Institute of Pathology (AFIP), Rawalpindi, from 1st January 2018 to 1st March 2018. Thirty cases of non small cell lung cancer diagnosed on H&E stain were included in the study. Patients’ gender, age, histologic type and histologic grade was noted. Immunohistochemistry for PDL1 was applied and the results were recorded. The data was analyzed by using computer software programme SPSS version 22. Descriptive statistics, frequencies and percentages were calculated. 3. Results: Out of the 30 patients, there were 24 (80%) males and 6 (20%) females. The mean age was 65.77±10.3 years. The most common histologic type was squamous cell carcinoma (73.3%, n=22) followed by adenocarcinoma (26.7%, n=8). The commonest histologic grade was moderately differentiated (70%, n=21) followed by well differentiated (16.7%, n=5) and poorly differentiated (13.3%, n=4). PDL1 expression was observed in 15 cases (50%). However, statistical significance was not observed between PDL1 expression and clinicopathological parameters. 4. Conclusion: The present study was conducted keeping in view the emergence of anti PDL1 targeted therapy for the treatment of non small cell lung cancer. Therefore, anti PDL1 therapy can be offered to patients showing immunohistochemical expression of PDL1. Keywords Non small cell lung cancer, PDL1, Immunohistochemistry


Primary Uterine Epithelioid Inflammatory Myofibroblastic sarcoma with IGFBP5-ALK

translocation

Dr. Huda Razvi, Dr. M. Y. Yu

Department of Anatomical and Cellular Pathology, Prince of Wales Hospital, Hong Kong

Introduction

Inflammatory myofibroblastic tumors (IMT) are potentially malignant tumors which may occur in various

sites of the body including the uterus, and they frequently harbor ALK translocations. Epithelioid

inflammatory myofibroblastic sarcoma (EIMS) is a rare variant of IMT with predominant epithelioid

morphology and more aggressive clinical course. It has been described primarily in the abdominal and

pelvic cavities. Herein we describe a case of EIMS occurring in the uterus of a 50-year-old lady. The patient

had a fulminant course and succumbed to the disease less than 3 months after the primary resection. To the

best of our knowledge, this is the first case to be described in the uterus. While the vast majority of cases

of EIMS have shown RANBP2 to be the ALK fusion partner, IGFBP5 has been identified in this case as a

new and previously undescribed fusion partner for EIMS.

Description

This is a case of a 50-year-old woman was known to have a 3 cm submucosal fibroid with anemia for 4

years. During a follow up for the fibroid, an ultrasound scan showed a heterogeneous mass within the uterus

and she underwent a total hysterectomy. At the time of the operation, the uterine mass was noted as well as

a few prominent left pelvic lymph nodes and para-aortic lymph node. No other lesions were present at the

time.

Gross examination showed a diffusely enlarged uterus. The endometrium was smooth and thin with a small

submucosal polypoid protrusion. Serial slicing showed an ill-defined, multinodular, tan, solid tumor

involving the full thickness of the myometrium. (figure 1). Microscopic examination showed an extensive

tumor within the myometrium with serosal extension. The tumor cells were arranged in sheets of

dyscohesive epithelioid cells with marked nuclear pleomorphism, prominent nucleoli and eosinophilic

cytoplasm. Many cells had eccentrically located nuclei. Mitotic figures were frequent. The background was

loose and edematous. Only a small focus of spindle cell component was found, which was located in the

small submucosal polypoid protrusion, showing hypocellular spindled cells set in a myxoid stroma. There

was an abrupt transition between the spindle cell area and the adjacent epithelioid tumor. Lymphovascular

invasion was frequent and lymph node metastasis was also present. There was no obvious inflammatory

cellular infiltrate amongst the tumor cells.

2 cm

2 cm

Figure 1. Gross images of hysterectomy specimen. A)

Diffusely enlarged uterus. B) Multinodular tumor

with full thickness involvement of myometrium.

A

B

ABSTRACT/POSTER PRESENTATION


Immunohistochemical studies showed that the epithelioid tumor cells were diffuse and strongly

immunoreactive for ALK-1 with focal CD30 positivity. The pattern of ALK staining was cytoplasmic with

some cells showing a perinuclear dot (figure 3). Positivity for progesterone receptor was present but not

estrogen receptor. They were negative for other lymphoid markers (LCA, CD3 CD20, CD79a, CD138),

epithelial markers (EMA, AE1/3, Cam5.2, E-cadherin), markers of smooth muscle differentiation (smooth

muscle actin, calponin, desmin, caldesmon, myogenin). In addition, they were also negative for CD10,

Cyclin D1, S100, SOX10, Melan A, MITF-1, HMB45, CD34, c-KIT (CD117). INI-1 staining was

preserved. Interestingly, the spindled cells were positive for smooth muscle markers (calponin, desmin,

smooth muscle actin) as well as ALK-1.

ALK break apart fluorescent in situ hybridization (FISH) test detected the presence of ALK translocation

and the diagnosis of epithelioid inflammatory myofibroblastic sarcoma (EIMS) was reached. Subsequent

RNA sequencing identified the translocation fusion partner as IGFBP5.

Figure 2. Morphology of uterine EIMS. A) Dyscohesive sheets of epithelioid cells. B) Bland spindle cell component with sharp transition to epithelioid tumor.

A B

Figure 3. ALK testing. A) Immunohistochemcial staining shows cytoplasmic and dot like staining. B) Break apart FISH for ALK.

A B


Post-operatively Crizotinib (an ALK inhibitor) was started. However, PET-CT scan around a month after

surgery showed a large pelvic mass as well as lung, peritoneal and nodal metastases. Involvement of the

intestine as well as bilateral hydronephrosis was present. The patient passed away less than 3 months after

surgery.

Discussion

Inflammatory myofibroblastic tumor (IMT) is a tumor that may occur anywhere in the body and is

considered to be of borderline malignant potential with a propensity for local recurrence but metastasis is

rare.1,2 They frequently harbor translocations involving the anaplastic lymphoma kinase (ALK) gene with

various fusion partners.3 Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is a developing entity

that is considered a rare variant of inflammatory myofibroblastic tumor (IMT). It differs from IMT by: (1)

having a predominantly epithelioid morphology, (2) showing a striking male predominance, (3) affecting

mainly the abdominal and pelvic cavities and (4) having an aggressive course of disease. 1,4 A total of 35

cases 4–22 have been described in the literature with 30 of those occurring intrabdominally or within the

pelvis. The remaining reported sites include: 2 cases present in the lung, one case in the pleura, one case in

the liver and one case in the ovary. The age ranged from 7 months old to 71 years old. The vast majority

of the cases occurred in males (n=28). To date, this is the first case of epithelioid inflammatory

myofibroblastic sarcoma to be described occurring in the uterus and the second case to occur in the female

genital tract with a previous case reported in a 15-year-old girl in the ovary. 11 The disease tends to have an

aggressive clinical course. In the 28 cases with follow up data available, 46% (n=13) of cases succumbed

to the disease within 3 to 36 months and another 28% (n=8) being alive with persistent disease.

Morphologically, all the reported cases were predominantly epithelioid with high grade cytological

features. However, other high grade features such as the presence of necrosis and maximum mitotic count

are inconsistently described in the literature, making it difficult to draw further conclusions as to whether

these histological factors can predict how aggressive a particular case of EIMS would be. Of note, 60% of

the reported cases had at least a minor spindle cell element.

Genetically, 16 of 17 cases of EIMS with molecular studies performed showed RANBP2-ALK fusion, the

remaining case harbored a EML4-ALK translocation. 18 Our case harbored a different ALK fusion partner.

IGFBP5 is an insulin growth factor binding protein that has been found to have variable roles in cell growth

and differentiation23 and to act as a tumor suppressor in some cancers24,25. While this is the first case to

describe an IGFBP5-ALK translocation in EIMS, it has been documented to occur in 6 cases of uterine

non-epithelioid IMT. 26,27 The finding that all these translocations also occur in the usual type of IMT 28

along with the fact that most EIMS have at least a focal spindle cell component further suggest that these

tumors are on the same biological spectrum of IMT.

Due to the rarity of this tumor in uterus, the pathologist is likely to face some difficulty in reaching the

diagnosis of EIMS. The main differential diagnoses may include various tumors with high grade epithelioid

morphology, including poorly differentiated carcinoma, malignant mixed Müllerian tumor, epithelioid

leiomyosarcoma, high grade endometrial stromal sarcoma, epithelioid rhabdomyosarcoma, anaplastic large

cell lymphoma, epithelioid gastrointestinal stromal tumor, malignant melanoma and perivascular

epithelioid cell neoplasm (PEComa). In cases where the tumor shows extra-uterine involvement, other

considerations such as malignant mesothelioma and epithelioid sarcoma also need to be considered.


Author/ year Case Age Sex AN/Atomic site Cells Necrosis Mitoses LVI F/U mnths Genetic

Marino-Enriquez 2011 1 59 yrs M SB Mesentery E+S Focal in 6 cases 1-18 per high

power field

N/A 12 (STD) N/A

2 41 yrs M Omentum 40 (ANED) RANBP2-ALK

3 6 yrs M Omentum 13 (AWD) N/A

4 28 yrs M SB Mesentery N/A N/A

5 63yrs M SB Mesentery 3 (STD) N/A

6 42yrs M Intra-abdominal 13 (AWD) N/A

7 7 mnth M Peritoneum 36 (STD) N/A

8 40 yrs M Peritoneum 28 (STD) N/A

9 31 yrs F SB Mesentery 11 (STD) N/A

10 6 yrs M Omentum+mesentery N/A RANBP2-ALK

11 39 yrs M SB Mesentery N/A RANBP2-ALK

Li 2013 12 19 yrs F Pelvic cavity E N/A 1-4/10 HPF N/A 3 (STD) RANBP2-ALK

13 39 yrs M Pelvic cavity 12 (AWD) RANBP2-ALK

Liu 2015 14 22 yrs M Pelvic cavity E+S Focal 1-5/HPF N/A ANED

(?duration)

RANBP2-ALK

Kimbara 2014 15 22 yrs M Pelvic cavity E+S N/A N/A N/A 10 (ANED) RANBP2-ALK

Kurihara-Hosokawa

2014

16 22 yrs M Pelvic cavity E+S N/A High N/A AWD

(?duration)

RANBP2-ALK

Zhou 2015 17 8 yrs M Pelvic cavity E+S N/A N/A N/A 8 (STD) N/A

Wu 2015 18 47 yrs F Pelvic cavity E N/A 2-3/10 HPF Present 8 (STD) RANBP2-ALK

Bai 2015 19 65 yrs M Colon Resection E N/A N/A N/A 18 (AWD) N/A

Yu 2016 20 37 yrs F Rectum E+S Focal necrosis in

3 cases

20/10 HPF LVI in

one

case

8 (ANED) N/A

21 55 yrs M SB Mesentery 10 (ANED) N/A

22 22 yrs M Mesentery of colon 14 (AWD) N/A

23 58 yrs F Omentum 8 (STD) N/A

24 15 yrs F Transverse colon 7 (ANED) N/A

Jiang 2017 25 45 yrs M Abdominal cavity E+S N/A 11/50 HPF N/A 2 (STD) EML4-ALK

Kozu 2014 26 57 yrs M Pleural cavity E N/A N/A N/A N/A RANBP2-ALK

Fu 2015 27 21 yrs M Lung E+S Focal 3/10 HPF N/A 4 (STD) N/A

Du 2018 28 26 yrs M Pelvic cavity E N/A N/A N/A 8 (STD) RANBP2-ALK

Fang, 2017 29 15 yrs F Ovary E+S Focal 1/10 HPF N/A 24 (AWD) RANBP2-ALK

Sarmiento 2015 30 71yrs M Lung E N/A N/A N/A 12 (ANED) N/A

Chen 2008 31 34 yrs M Liver E N/A 2/10HPF N/A 5 (STD) RANBP2-ALK

Ma 2003 32 7 yrs M Abdominal cavity E N/A N/A N/A N/A RANBP2-ALK

33 7 mths M Abdominal cavity E+S N/A Infrequent N/A N/A RANBP2-ALK

Hallin 2019 34 N/A M Abdominal cavity E N/A N/A N/A N/A N/A

Xu, 2019 35 28 M Abdominal cavity E N/A N/A N/A 16 (AWD) RANBP2-ALK

ALK-G1269A

Table 1. Clinicopathological features of reported EIMS cases. SB, small bowel; yrs, years; mnths, months; STD, succumb to disease; ANED, alive with no

evidence of disease; AWD, alive with disease; E, epithelioid; S, spindled.


Apart from immunohistochemical panel to exclude the above listed differential diagnoses, careful gross

inspection and thorough sampling are warranted to identify a spindle cell component and search for other

diagnostic clues.

In summary, clinical, histological and molecular features of EIMS are becoming better clarified as it is

being found in more locations and more new ALK fusion partners are being identified. Given its more

aggressive clinical course and potential benefit for ALK inhibitor therapy, awareness of this rare entity with

its inclusion into the differential diagnosis list of epithelioid malignant uterine neoplasms would help to

provide a correct diagnosis and timely targeted therapy.

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28. Sokai A, Enaka M, Sokai R, et al. Pulmonary Inflammatory Myofibroblastic Tumor Harboring EML4-ALK Fusion Gene.

Jpn J Clin Oncol. 2014;44(1):93-96. doi:10.1093/jjco/hyt173


ABSTRACT/POSTER PRESENTATION Perivascular epithelioid cell neoplasm (PEComa) in the larynx: a case report BMW Lam; AKH Tsang Department of Pathology, Yan Chai Hospital, Hong Kong PEComas are a family of mesenchymal tumours composed of variable amounts of smooth muscle, adipose tissue and thick-walled blood vessels. They share overlapping morphology, immunohistochemistry, and ultrastructure and occur in a variety of visceral and soft tissue sites throughout the body. The defining histological features are epithelioid cells with a perivascular distribution containing clear to pale eosinophilic cytoplasm and a round to oval centrally located nucleus with an inconspicuous nucleolus. Immunohistochemically, co-expression of melanocytic (HMB-45 and/or Melan-A) and myoid markers is characteristic. Herein we report a case of PEComa occurring in the larynx of a 32-year-old man who presented with a bulging mass over the right false cord. The tumour shows classic histologic features of PEComa but staining for HMB-45 is negative and that for Melan-A is only focal patchy. The differential diagnosis of PEComas is fairly broad, and depends on the morphology (epithelioid vs spindled) and location of the neoplasm. Assessment of both the morphologic features and immunohistochemical profile is important for diagnosis of this rare entity, a small number of which may recur or metastasize, and for which clear criteria for malignancy are yet to be established.


ABSTRACT/POSTER PRESENTATION PERFORATION OF MIXED ADENONEUROENDOCRINE CARCINOMA OF THE STOMACH: A CASE REPORT

1Christine Mae G. Olivar, 1Michelle Anne M. Encinas-Latoy, 1Andrew D. Dimacali and 2Mark Augustine S. Onglao 1Department of Laboratories and 2Department of Surgery University of the Philippines-Philippine General Hospital, Manila, Philippines Gastric mixed adenoneuroendocrine carcinoma is a rare tumor with limited studies on its natural course and prognosis. We report a case of a 45-year-old Filipino male who presented with sudden severe abdominal pain after a four-month history of upper gastrointestinal tract obstruction. Emergency laparotomy showed a perforated gastric tumor. Immunohistologic examination of the tumor revealed mixed adenoneuroendocrine carcinoma (MANEC) with Ki-67 index of 70-75%. Expression for p53 was positive on both the adenocarcinoma and neuroendocrine components of the tumor. The patient died one month after the diagnosis.


ABSTRACT/POSTER PRESENTATION AN AUTOPSY OF SCLEROSING ENCAPSULATING PERITONITIS FROM MYCOBACTERIUM FORTUITUM IN A PATIENT WITH MULTIPLE MYELOMA 1Christine Mae G. Olivar, 1,2Eugene G. Odoño I and 3 Marie Gene D. Cruz 1Department of Laboratories and 3Department of Medicine, University of the Philippines-Philippine General Hospital, Manila, Philippines 2Department of Pathology, University of the Philippines, College of Medicine, Manila, Philippines.

Sclerosing encapsulating peritonitis (SEP), also known as “abdominal cocoon syndrome”, is a rare cause of intestinal obstruction due to fibrous encapsulation of abdominal visceral organs. We report a case of a 50-year-old Filipino male with multiple myeloma who presented with one-year history of abdominal enlargement. The patient was eventually admitted in an intensive care unit but expired from hospital-acquired infection. Autopsy findings showed a thick fibrous membrane completely encapsulating the abdominal organs. There are also caseous lesions in the peritoneal cavity, spleen, adrenal glands, gallbladder, small intestine, colon, appendix and lymph nodes. Histologic examination revealed poorly-formed granulomas with extensive caseation necrosis and absence of giant cells. Microbiologic studies showed Mycobacterium fortuitum infection. Other autopsy findings include disseminated infection of Schistosoma japonicum ova and gallstones in the hepatobiliary tree. This is the first documented case of SEP in a patient with multiple myeloma who acquired Mycobacterium fortuitum infection.


ABSTRACT/POSTER PRESENTATION Heart transplant for multiple recurrences of familial cardiac myxomas in an adolescent patient: a case report and literature review Thiyaphat Laohawetwanit1, Poonchavist Chantranuwatana1, Pat Ongcharit2 1Department of Pathology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand 2Division of Cardiothoracic Surgery, Department of Surgery, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand Primary cardiac tumors are rare, with an incidence rate of 0.0017% to 0.19% in unselected autopsies. [1] The majority of these tumors are benign. Rhabdomyomas and myxomas are the most common primary tumors of the heart in children and adults, respectively. Cardiac myxoma is the most common primary neoplasm of the cardiac muscle commonly arising from the endocardium. It can be detected in all age groups (prenatally to 97 years old). Mean age at presentation is between the fourth and seventh decades of life. More than 90% of cardiac myxomas occur sporadically. Less than 10% of them are associated with Carney complex (myxoma syndrome), which is an autosomal dominant pattern of inheritance. This tumor is commonly seen in younger patients without sex predominance. [2] High recurrence rate is reported for familial cardiac myxomas; nevertheless, multiple recurrences are extremely rare. [3] In this report, we describe a patient having multiple recurrences of multicentric cardiac myxomas and underwent cardiac transplantation. This is the first report of such a case at King Chulalongkorn Memorial Hospital. After the patient had undergone heart transplantation, the clinical course was uneventful. Nine months later, she stopped immunosuppressive agents by herself and developed subacute progressive dyspnea. Finally, she developed septic shock and passed away. Compared with the previously reported cases, the current case was presented with the early-onset disease. The presented case is the first case of end-stage heart disease due to multiple recurrences of familial cardiac myxomas to undergo heart transplant at our institution.


Reference:

1. Reynen K. Cardiac myxomas. N Engl J Med. 1995;333(24):1610-7. 2. Travis WD, Brambilla E, Burke A, Marx A, Nicholson AG. WHO

Classification of Tumours of the Lung, Pleura, Thymus and Heart. Lyon: International Agency for Research on Cancer; 2015.

3. Stratakis CA, Kirschner LS, Carney JA. Clinical and molecular features of the Carney complex: diagnostic criteria and recommendations for patient evaluation. J Clin Endocrinol Metab. 2001;86(9):4041-6.


ABSTRACT/POSTER PRESENTATION A case report of gastric type adenocarcinoma of the uterine corpus, in a patient with congenital adrenal hyperplasia Chun Kei Cheung, Wing Cheuk Wong Department of Clinical Pathology, Pamela Youde Nethersole Eastern Hospital, Hong Kong There are only a few reported cases of gastric-type adenocarcinoma of the uterine corpus in the literature. It is regarded as a variant of mucinous adenocarcinoma that exhibits pyloric differentiation and is often associated with poor prognosis. We present a case of gastric type adenocarcinoma of the uterine corpus in a 69 year old patient who was diagnosed with 46, XX disorder of sex development (46,XX DSD) due to congenital adrenal hyperplasia, secondary to 21-hydroxylase deficiency. The patient was brought up as a male with history of hypospadias until investigations at the age of 64 for lower urinary tract symptoms revealed absence of testes and the presence of uterus with bilateral small ovaries. Biochemical workup and genetic testing confirmed the diagnosis of 21-hydroxylase deficiency. Cytogenetics revealed 46 ,XX karyotype. Five years after bilateral gonadectomy were performed, the patient presented with lower abdominal pain together with distended uterus on CT scan, suspecting haemoperitoneum. Hysterectomy was performed and revealed a tumour with heterogeneous yellowish to tan appearance in the endometrial cavity. Müllerian malformation with absence of cervical structure and the lower part of uterus continuous with a vagina-like structure were noted. The tumour showed invasion to the outer half of the myometrium. Microscopically, the endometrium was replaced by mucinous glands with columnar lining and moderate nuclear atypia. The mucinous glands possessed moderate to abundant amount of apical eosinophilic mucin, foamy cytoplasm and distinct cell borders. Mitotic activity was occasionally noted, including atypical forms. Immunohistochemically, the tumour cells were diffusely positive for CK7 and MUC6, focally weakly positive for PAX8, while negative for CK20 and CDX2, WT1, estrogen receptor (ER) and progesterone receptor (PR). The tumour cells also exhibited wild-type pattern for p53. Whole pelvic irradiation was given and the patient developed peritoneal deposits in peritoneum, lung and lymph node metastasis within 6 months postoperatively. Gastric type adenocarcinoma of the uterine corpus is probably underrecognized and biologically distinct from endometrial mucinous carcinoma of Müllerian type. Recognition of the characteristic histological and immunohistochemical features is important for diagnosis of this aggressive neoplasm.


ABSTRACT/POSTER PRESENTATION Clinicopathological Features of Melanotic and Non-melanotic Oncocytic Lesions of the Nasopharynx. Joanna K. M. Ng, MBBS, Joshua J. X. Li*, MBChB, Amy B. W. Chan, FHKCPath, FHKAM (Path) Department of Anatomical and Cellular Pathology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Oncocytic metaplastic lesions of the nasopharynx are rare benign entities which are divided into melanotic and non-melanotic forms. Less than 40 non-melanotic and 30 melanotic cases have been reported in the literature. We present the largest known case series to date of melanotic oncocytic metaplasia and more than 20 cases of non-melanotic oncocytic metaplasia. Clinical, endoscopic, histologic and immunohistochemical features were reviewed. Most cases presented in males starting from their late adulthood. Compared to its non-melanotic counterpart, all cases of melanotic oncocytic metaplasia had a smoking history (p = 0.041). All cases of melanotic oncocytic metaplasia are negative to melanocytic markers (S100, HMB-45, Melan-A and MiTF). Although no disease-related mortality was recorded, concurrent melanoma and nasopharyngeal carcinoma were seen in two cases.


ABSTRACT/POSTER PRESENTATION Cutaneous plasmacytosis with Polyclonal Hypergammaglobulinemia in a 39-year-old woman—report a case Hui-Ting, Hsu Department of Surgical Pathology, Changhua Christian Hospital, Taiwan Introduction Cutaneous plasmacytosis (CP) is a rare skin disorder characterized by multiple reddish-brown nodules or patches with polyclonal plasma cell proliferation and association with polyclonal hypergammaglobulinemia. It has most often been reported to affect the trunk and abdomen in middle-aged adults and is predominantly seen in Asians. The etiology and pathogenesis is poorly understood, and elevation of the interleukin- 6 (IL-6) level is observed in some cases. There are no consensus treatment modalities for CP. Herein we reported a case of cutaneous plasmacytosis and hypergammaglobulinemia with polyclonal gammopathy in a middle-aged woman with long term follow up. The case The 39-year-old woman presented with multiple skin rashes for more than five years. She ever took oral prednisolone for six months, but no improvement was achieved. There were new indurated lesions developing on the left arm and left inner thigh. She denied arthralgia nor joint stiffness. The physical examination revealed multiple brown-colored linear streaks, patches or papules over trunk, abdomen, left arm and left thigh. There was no pale conjunctive, no lymphadenopathy, nor pitting edema of the joints. The serum lab tests revealed elevated ESR (52 mm/hr), ANA (Homogeneous pattern): 1:80, ANA (Fine Speckled pattern): 1:80, ANA (Anti-cytoplasmic staining pattern): 1:80, Anti-SSA: (-), and Anti-SSB: (-). Lupus panniculitis or granulomatous disease was suspected. Therefore, the patient received a skin biopsy for further definite diagnosis. Pathology findings The skin biopsy was performed on the left inner thigh. Microscopically, the epidermis showed acanthosis with elongated and board rete ridges and hyperpigmentation. No interface dermatitis was seen. There were foci of deep and superficial, perivascular and periadnexal infiltrate, composed predominantly of mature lymphocytes and plasma cells without atypia. No panniculitis, material deposition, nor vasculitis is identified. The immunohistochemical study demonstrated some CD20-positive B lymphocytes,


admixed with abundant CD138-positive plasma cells and rare CD23-positive follicular dendritic cells. No definite light chain restriction was evident under the Kappa and Lambda light chain immunostains (Fig3). The IgG4 immunostain revealed no increased IgG4-positive plasma cells. The HHV8 and syphilis immunostains were both negative. In all, cutaneous plasmacytosis was diagnosed. Follow up Further serum tests were performed. The HIV Ag/Ab comb test was nonreactive. The rapid plasma reagin (RPR) was non-reactive, and T. pallidum Ab confirmation (TPPA) test was negative. The serum protein electrophoresis reported hypergammaglobulinemia with polyclonal gammopathy. The β2-microglobulin is within normal limit (1.53 mg/L), and no elevated LDH (102 U/L) was found. Then, the patient received phototherapy (NB UVB f 200 mj/cm2) for skin lesions. The patient was regularly followed up for two years, and no serum paraprotein was detected by immunotyping/immunofixation electrophoresis recently. She received periodic serum protein electrophoresis every half a year, and no monoclonal gammopathy was detected. Discussion Cutaneous plasma cell infiltration of the skin may be due to a variety of etiologies, including chronic infection, connective tissue disease, plasma cell neoplasm and other disorders with plasma cell proliferation. Cutaneous plasmacytosis is a rare clinical entity occurring without any known underlying disease. Systemic involvement may be manifested as hepatosplenomegaly, increased plasma cell infiltrate in the bone marrow, superficial lymphadenopathy and lymphocytic interstitial pneumonia of the lung. Most cases follow a chronic and benign clinical course, and there is no agreement on treatment strategy. The accurate diagnosis of cutaneous plasmacytosis is often not easy and differential diagnosis includes marginal zone B cell lymphoma, extramedullary plasmacytoma, plasma cell leukemia with secondary skin involvement, lymphoplasmacytic lymphoma and Waldenstrom's macroglobulinemia. Further studies are required to fully elucidate the pathogenesis of this uncommon but increasingly recognized condition. Reference 1. Cutaneous Plasmacytosis: A Clinicopathologic Study of a Series of Cases and Their Treatment Outcomes. Han XD, Lee SSJ, Tan SH, Chong WS, Ng SK, Ooi MGM, Goh CL. Am J Dermatopathol. 2018 Jan;40(1):36-42. doi: 10.1097/DAD.0000000000000907.


2. Cutaneous Plasmacytosis: Report of a Case. YW Yang, Sindy Hu, TT Kuo, HS Hong. Dermatol Sinica 21 : 97-101, 2003 3. Cutaneous plasmacytosis: A report of five cases with immunohistochemical evaluation for HHV-8 expression. Jayaraman AG, Cesca C, Kohler S. Am J Dermatopathol. 2006 Apr;28(2):93-8.


ABSTRACT/POSTER PRESENTATION Composite diffuse large B-cell lymphoma and histiocytic sarcoma at the tonsil, a case report Liu Kwan Leung Tuen Mun Hospital, Hong Kong. Introduction Histiocytic sarcoma is a rare neoplasm with only a few series reported. It is usually an aggressive neoplasm with a poor response. The etiology is unknown. Some are associated with a B-cell lymphoma and may show clonal Immunoglobulin rearrangement [2]. We herein describe a case of composite diffuse large B-cell lymphoma and histiocytic sarcoma at the tonsil with related molecular study done. Case History The patient, a 61-year-old man, with history of hypertension, otherwise good past health, presented with globus sensation and left neck mass for a few weeks. Physical examination revealed presence of left tonsil mass; there were also left neck upper level II and level III matted lymph nodes. Biopsy of the left tonsil mass was performed. Diagnosis was Composite diffuse large B-cell lymphoma and histiocytic sarcoma. The patient was subsequently given chemotherapy (R-CHOP) and radiotherapy. Pathology Microscopic appearance and immunohistochemistry Sections show 2 pieces of mucosal tissue. In one piece there is conventional diffuse large B-cell lymphoma consisting of nodular proliferation of large neoplastic lymphoid cells with irregular nuclei and prominent nucleoli. They are LCA+, CD20+, CD79+, PAX5+, MUM1-, CD10-, CD5-, BCL6 and CD30-. No follicular dendritic cell network is found. In the other piece of tissue, there are dense sheets of irregular histiocytic cells. Some possess abundant vacuolated cytoplasm, vesicular chromatin and prominent nucleoli, whereas some have irregular hyperchromatic nuclei and densely eosinophilic cytoplasm. Vague granuloma is also noted. These histiocytic cells are positive for CD68 (KP1 and PGM1), CD4, lysozyme and CD33, but negative for lymphoid markers(LCA, CD20, CD79, PAX5), MPO, CD163, CD1a, and follicular dendritic cell markers. Molecular findings


The specimen was macrodissected into 2 components (A: diffuse large B cell lymphoma component and B: Histiocytic sarcoma) and was sent separately for study for rearrangement of Immunoglobulin heavy (IGH) gene by PCR (Genomic DNA was extracted from formalin fixed paraffin embedded tissue. PCR was performed using InvivoScribe IdentiClone IGH Gene Clonality Assay Kit which employs BIOMED-2 recommended PCR primers. The PCR products were analyzed using capillary electrophoresis.) A (Diffuse large B cell lymphoma component) : IGH gene tube E (DH7-JH): a single clonal peak (112.3 bp) was detected in a polyclonal background. B (Histiocytic sarcoma component) : no clonal peak detected. polyclonal irregular pattern only. Discussion Histiocytic sarcoma is a rare malignant neoplasm showing morphologic and immunophenotypic evidence of histiocytic differentiation. It is more or less a diagnosis of exclusion as it is necessary to rule out other disease (e.g. anaplastic large cell lymphoma and diffuse large B cell lymphoma) by extensive immunophenotypical panel [1]. However, the 2008 WHO classification no longer strictly requires the absence of clonal immunoglobulin heavy chain (IGH) or T-cell receptor (TCR) gene rearrangement for the diagnosis of Histiocytic sarcoma. Recent studies demonstrated that histiocytic sarcoma that occurs subsequent to or concurrent with B-cell/T-cell neoplasms generally show clonal IGH and/or TCR gene rearrangement[2,3,6,7]. These findings suggest the possibility of transdifferentiation of the two otherwise morphologically and immunohistochemically distinctive neoplasms. In addition, a recent study suggested clonal IG gene rearrangements may be detected in sporadic histiocytic sarcoma [5]. In our case, there are 2 identifiable distinct population of tumors cells (diffuse large B cell lymphoma and histiocytic sarcoma), with clonal IGH rearrangement detected in the lymphomatous component but not in the sarcomatous component. This may suggest that histiocytic sarcoma may be more heterogeneous than we have initially thought and transdifferentiation may be just one of the mechanisms for a concurrent tumor. Given the rarity of this tumor, more study will be required to delineate the nature of this neoplasm.


Reference 1. Takahashi, Emiko, and Shigeo Nakamura. "Histiocytic sarcoma: an updated literature review based on the 2008 WHO classification." Journal of Clinical and Experimental Hematopathology 53.1 (2013): 1-8. 2. Wang, Endi, et al. "Sequential development of histiocytic sarcoma and diffuse large b-cell lymphoma in a patient with a remote history of follicular lymphoma with genotypic evidence of a clonal relationship: a divergent (bilineal) neoplastic transformation of an indolent B-cell lymphoma in a single individual." The American journal of surgical pathology 35.3 (2011): 457-463. 3. Feldman, Andrew L., et al. "Clonally related follicular lymphomas and histiocytic/dendritic cell sarcomas: evidence for transdifferentiation of the follicular lymphoma clone." Blood 111.12 (2008): 5433-5439. 4. Hornick, Jason L., Elaine S. Jaffe, and Christopher DM Fletcher. "Extranodal histiocytic sarcoma: clinicopathologic analysis of 14 cases of a rare epithelioid malignancy." The American journal of surgical pathology 28.9 (2004): 1133-1144. 5. Chen, Wei, et al. "High frequency of clonal immunoglobulin receptor gene rearrangements in sporadic histiocytic/dendritic cell sarcomas." The American journal of surgical pathology 33.6 (2009): 863-873. 6. Hure, Michelle C., et al. "Histiocytic sarcoma arising from clonally related mantle cell lymphoma." Journal of Clinical Oncology 30.5 (2011): e49-e53. 7. Shao, Haipeng, et al. "Clonally related histiocytic/dendritic cell sarcoma and chronic lymphocytic leukemia/small lymphocytic lymphoma: a study of seven cases." Modern Pathology 24.11 (2011): 1421.


ABSTRACT/POSTER PRESENTATION A case of papillary thyroid carcinoma with squamous differentiation a diagnostic pitfall Dr. Aysha Aljawder MD, Dr. Maribel Lacumbra MD, Dr. Paul Choi FRCPA FHKPath Department of Anatomical and cellular pathology, Prince of Wales Hospital The Chinese University of Hong Kong Introduction Papillary thyroid carcinoma with squamous differentiation (PTC-SD) is a poorly understood pathologic finding of unknown clinical significance that can be a diagnostic pitfall between primary squamous cell carcinoma (SCC) and metastatic squamous carcinoma. The presence of squamous components in thyroid tissue is a frequent finding and has been described in the literature as suspected to be metaplastic or maldevelopment of the thyroglossal duct remnants. Materials and Methods We report a case of a 71 year old man who presented with a neck mass and shortness of breath who underwent total laryngectomy and neck lymph node dissection of an infiltrative thyroid mass measuring 6 cm x 4 cm x4 cm. Microscopic examination showed a papillary carcinoma with squamous differentiation, consists of papillary architecture with fibrovascular core lined by tumor cells that exhibit mild nuclear pleomorphism, small distinct nucleoli, nuclear groves, and pseudo-nuclear inclusion. More than 50% of the tumor shows squamous differentiation with infiltration to the surrounding soft tissue and involvement of the left and right excisional margins. Subtotal neck dissection showed 11 involved lymph nodes. Immunohistochemistry stains show the TTF-1 was diffusely positive in the papillary and focally in the squamous component, PAX 8 was positive in the papillary component only, and p63 was negative in both components. BRAF V600E mutation by polymerase chain reaction (PCR) was positive in both the papillary and squamous components. Discussion Neoplastic squamous cells, when found in the thyroid is crucial to exclude any metastatic squamous cell carcinoma, direct extension from an extra-thyroidal primary tumor and primary thyroid carcinoma with squamous differentiation before making a diagnosis as this has impact on potential treatment. In our case, histological association of the papillary thyroid carcinoma with squamous differentiation and the apparent


absence of a primary squamous cell carcinoma along with negative P63 staining and BRAF V600E mutation detected in both papillary and squamous components, the squamous cell component was believed to be metaplasia in the papillary cell carcinoma. On follow-up, the patient had a recurrent rapidly progressing lesion extending to the mediastinum compromising the airways leading to death. Conclusion Squamous differentiation is a frequent finding in papillary thyroid carcinoma with unknown clinical significance. Pathologic nature and poor long-term outcomes can be debatable. This case provides further suggestion that papillary cell carcinoma with squamous differentiation showed advanced stage behavior and required further investigation to reach the correct diagnosis.


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