1130-0108/2016/108/1/43-47Revista española de enfeRmedades digestivasCopyRight © 2016 aRán ediCiones, s. l.

Rev esp enfeRm dig (Madrid)Vol. 108, N.º 1, pp. 43-47, 2016

CASE REPORT

ABSTRACT

We report a case of a 50-year-old woman who presented to the emergency department with large bowel obstruction and anemia. The initial imaging study suggested an inoperable rectal tumor with involvement of surrounding structures. In this paper, we discuss the diagnostic work-up of this patient with a diagnosis of pelvic/perirectal inflammatory myofibroblastic tumor (IMT). IMT is a rare tumor with intermediate malignant potential that frequently mimics clinical and imaging features of malignancy. Additionally, to the best of our knowledge, this is the first case of a pelvic IMT that regressed without surgical excision.

Key words: Inflammatory myofibroblastic tumor. Rectal cancer. Endoscopic ultrasound. Magnetic resonance imaging.

INTRODUCTION

We report a case of a pelvic/perirectal inflammatory myofibroblastic (IMT) in which the initial imaging study suggested an inoperable rectal cancer and illustrate the challenges of pre-operative diagnosis. In addition, we pres-ent the endoscopic ultrasound and fine needle aspiration findings of this tumor.

IMTs are rare mesenchymal tumors that can involve virtually any organ, with the lung being the most frequent location (1). Due to its paucity and misuse of the term “inflammatory pseudotumor” as synonym for IMTs, its true prevalence and incidence are unknown (2). According to the World Health Organization classification IMTs are considered to have intermediate biological potential due to the 25% rate of local recurrence and up to 5% of distant metastasis (3). Surgical resection is usually the definite treatment option, in rare cases complemented with che-motherapy and/or radiation (4).

CASE REPORT

A 50-year-old woman presented to the emergency department with lower abdominal pain, fever, anorexia, progressive constipation and loss of 11 kg for one month. She had a history of depression and iron deficient chron-ic anemia and denied smoking and drinking habits. The patient was medicated with estazolam and oral iron. There was no family history of cancer.

On physical examination, lower abdomen tenderness and abdominal distension were noted. Gynecological examination revealed extrinsic bulging of both anterior and posterior vaginal sacs, which appeared hard and painful, with no evidence of mucosal lesions.

The laboratory panel was remarkable for microcytic anemia (hemoglobin 9.4 g/dl, reference 11.5-18); low mean corpuscular volume (69.4 fl, reference 76-96), ele-vated white blood cell (19,800/mm3, reference 4-11,000, 84% neutrophils) and platelet (924,000/mm3, reference 140-400,000) counts and a C-reactive protein of 23.3 mg/dl (reference < 0.2). The renal function was within the normal limits. There was no elevation of tumor markers, including carcinoembryonic antigen and carbohydrate anti-gen 19.9.

Contrast-enhanced abdominopelvic computed tomog-raphy revealed an obstructive transmural rectal tumor, centered at the right rectum wall, extending anteriorly to the mesorectum and with ill-defined boundaries with the uterus and the vaginal dome (Fig. 1).

Fibrosigmoidoscopy revealed a rectal stenosis with nor-mal underlying mucosa and passable with moderate pres-sure. A pelvic magnetic resonance imaging was ordered to further characterize the local extent of the tumor and showed a transmural rectal tumor with 9.5 cm length.

Received: 20-03-2015Accepted: 28-03-2015

Correspondence: Lídia Roque Ramos. Gastroenterology Department. Hos-pital Garcia de Orta. Avenida Torrado da Silva, 2801-951 Almada, Portugale-mail: lidia.roque.ramos@gmail.com

Roque-Ramos L, Matos AP, Pinto-Marques P, Machado G, Nogueira J, Ramal-ho M. Pelvic inflammatory myofibroblastic tumor mimicking a rectal cancer. Rev Esp Enferm Dig 2016;108:43-47.

Pelvic inflammatory myofibroblastic tumor mimicking a rectal cancerLídia Roque-Ramos1, António P. Matos2, Pedro Pinto-Marques1, Gabriela Machado3, Joana Nogueira4 and Miguel Ramalho2

1Gastroenterology, 2Radiology, 3Surgery, and 4Pathology Departments. Hospital Garcia de Orta. Almada, Portugal

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The tumor extensively contacted the posterior wall of the vagina and uterus, ovaries and sacrum, suggesting direct invasion of the surrounding structures. Lymphadenopa-thies were observed in the mesorectum and at the right internal iliac chain (Fig. 2). Subsequent chest computed tomography was unremarkable.

Considering the presumed diagnosis of a locally advanced rectal tumor and the symptomatic bowel obstruc-tion, an emergent derivative colostomy was performed. Intra-operatively, a rectal tumor adhering to the uterus and pre-sacral area was observed.

To further characterize this rectal stenosis, an endoscop-ic ultrasound (Olympus UCT140 AL5) was performed. The normal fi ve-layered appearance of the rectal wall was preserved while an ill-defi ned extrinsic hypoecoic mass infi ltrated the perirectal fat. These features were suspicious for extrinsic tumor infi ltration and fi ne needle aspiration with a 19 G procore needle was performed (Fig. 3). The

Fig. 1. Post contrast (iopromide [Ultravist 370®]) pelvic axial computed tomography image (BrightSpeed® 16 slice, GE Healthcare, Milwaukee, Wisconsin, USA) shows a right-sided heterogeneous and enhancing tumor (arrows) extending from the rectum with contact with the uterus.

Fig. 2. Pelvic magnetic resonance imaging (1.5-T, GE-Signa HDxÒ, GE Healthcare) after derivative colostomy. A. Axial contrast-enhanced [gadoterate meglumine (Dotarem®, Guerbet)] fat-suppressed T1-weighted image shows heterogeneous tumor enhancement with rectal encasement (asterisk), spreading along the mesorectum and abutting the uterus (arrow). B. Axial T2-weighted image shows a tumor with intermediate signal arising from the right rectal wall. Right-sid-ed mesorectal enlarged lymph nodes are seen (curved arrow). The hipointense line of the mucosa seems preserved, suggesting a deeper origin rather than the mucosa (arrow). C. Sagittal T2-weighted image shows the longitudinal extent of the tumor, and its relation with the sacrum, vaginal dome and cervix.

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cellblock obtained muscle cells and stroma with an exu-berant infl ammatory cell infi ltrate composed of B and T lymphocytes and histiocytes, consistent with an infl am-matory process.

During the follow-up, the patient maintained abdom-inal pain, low-grade fever and elevated infl ammatory markers, despite being medicated with intravenous cefu-roxime and ciprofl oxacin. Since a defi nitive diagnosis was lacking a second-look surgery was performed, which revealed a whitish infi ltrating mass extending from the pre-sacral region to the uterus, involving the ovary, rec-tum and ileo-cecal appendix. Hysterectomy, bilateral sal-pingo-oophorectomy and appendectomy were performed. Surgical macrobiopsies revealed a spindle cell prolifer-ation with numerous infl ammatory cells, predominantly lymphocytes and plasma cells, in an eosinophilic collag-enized stroma. No atypia, cellular mitoses or necrosis was observed. Immunohistochemical staining for smooth muscle actin antibody was positive in the spindle cells. There was no expression of anaplastic lymphoma kinase (ALK), CD34, CD117 or S100 (Fig. 4). These fi ndings were consistent with infl ammatory myofi broblastic tumor in the cellular phase. Additionally, a chronic right-sided salpingitis with acute infl ammatory infi ltrate was identi-fi ed and the sample was negative for fungi and acid fast bacilli.

Shortly after the procedure the patient became asymp-tomatic with gradual normalization of laboratory param-eters, including hemoglobin (14 g/dl), leucocytes (5,700/mm3), platelets (291,000/mm3) and C-reactive protein (0.1 mg/dl). Due to the favorable course of the disease and histopathological fi ndings, the clinical decision was to fol-low up without further therapy. Bowel reconstruction was successfully performed. The magnetic resonance imaging exam repeated after one year showed complete regression of the pelvic mass (Fig. 5).

DISCUSSION

Infl ammatory pseudotumor (IPT) is a term fi rst used in 1985 and describes the histological appearance of a bland spindle cell proliferation with prominent infl ammatory infi ltrate. Over the last decades it has became clear that this morphological terminology was broad and included several clinic-pathological entities with different cell lin-eage and biological behavior. For this reason some authors advocate dividing IPT in secondary, when these lesions are believed to represent a reparative reaction to infection, infl ammation or trauma, and primary or idiopathic when the etiology is unknown (5). Idiopathic IPT probably rep-resent true IMT, a neoplastic entity that emerged from the heterogeneous group of IPT for it’s distinct clinical, patho-logical and molecular features (2). IMT have an intermedi-ate biological behavior and should be distinguished from benign reactive secondary IPT and malignant tumors with a prominent infl ammatory component such as leiomyosar-comas. Although IMT are more frequent in children and adolescents they can occur in older patients such as seen in our patient. Virtually any organ can be involved, with the most common locations being the lung, abdominopelvic region and retroperitoneum (2).

Patients may be asymptomatic, particularly when the tumor is a small solitary mass; present with local mass effects such as abdominal pain, vomiting, constipation, chest pain or cough; and/or have systemic manifesta-tions, including fever, weight loss and malaise, report-ed in 15-30% of cases. Laboratory work-up refl ects an inflammatory process and includes anemia, thrombo-

Fig. 3. Linear endoscopic ultrasound (Olympus UCT 140 AL5) depicted an ill-defi ned hypoecoic mass infi ltrating the peri-rectal fat. Fine-needle aspiration was performed with a 19 G procore needle.

Fig. 4. Histological examination of the peri-rectal mass: A. The tumor is composed of a spindle cell proliferation with a collagenized stroma and a diffuse infl ammatory infi ltrate, with scattered aggregates (arrow), and with numerous lymphocytes and plasma cells. B. Some epithelioid tumor cells with eosinophilic nucleoli and amphophilic cytoplasm can be seen intermingled with the lymphoplasmacytic infl ammation. C. The tumor has positive immunoreactivity for smooth muscle actin. D. No immunoreactivity for anaplastic lymphoma kinase protein.

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cytosis, leucocytosis, increased C-reactive protein and sedimentation rate, hypoalbuminemia and polyclonal hypergammaglobulinemia (1,2,5). Imaging features, are variable and nonspecific and may mimic malignant pro-cesses with aggressive features such as mural infiltration and extravisceral extension (1,6). Indeed, the reported patient presented with constitutional symptoms and bow-el obstruction, as well as increased serum inflammation markers, anemia and an apparent rectal tumor invading surrounding organs on both computed tomography and magnetic resonance imaging.

As in most malignancies the definitive diagnosis of IMT relies on histology (6). There are only 3 cases of abdominal IMT reported where endoscopic ultrasound was performed (7-9). In one case, the IMT was located in the spleen (10), and fine needle aspiration allowed definite histological diagnosis. In the remaining two cases, gastric hypoecoic subepithelial lesions were evaluated with endoscopic ultra-sound without fine needle aspiration and the final diagnosis was obtained after gastrectomy (7) and endoscopic submu-cosal resection (8). In our case, the endoscopic ultrasound evaluation demonstrated a preserved five-layer rectal wall structure, suggesting an extramural process. The fine nee-dle aspiration pointed towards an entity characterized by the presence of abundant inflammatory cells and stroma. However, since soft tissue sarcomas can be accompanied by an inflammatory reaction and the patient had an exu-berant clinical presentation, malignancy couldn’t be confi-dently ruled out and the final diagnosis was obtained after intra-operative macrobiopsies.

Surgical excision is considered the treatment of choice (9) and adjuvant therapy with chemotherapy and/or radi-ation is controversial (4). In our case the infiltrating and

diffuse nature of the pelvic mass precluded a complete excision and a decision to follow-up was taken. Zhao et al. recently published a literature review with 38 patients with abdominal IMT that regressed without surgery, 31% of whom were treated with NSAIDs, steroids or antibiot-ics. The liver was the most common location (11). Inter-estingly, shortly after surgery, our patient became asymp-tomatic and the serum inflammatory markers normalized. The magnetic resonance imaging performed one year later showed complete resolution of the pelvic mass. Regression without surgical tumor resection is uncommon (1). To the best of our knowledge this is the first case of a pelvic IMT that regressed without surgery, with short-term intravenous antibiotics being the only therapies given considering the suspicious of infection.

Recurrence rates range from less than 2% in the lung up to 25% in extrapulmonary locations. Distant metastases are rare (< 5%) and the most common sites are lung, brain, liver and bone (2). Prognostic factors are still undefined. Tumor size and morphologic features are not reliable prognostic factors, however aneuploidy may indicate a more aggressive course (3). Rearrangements involving the ALK locus on chromosome 2p23 have been demonstrated in approximately 50% of IMTs, based on immunohisto-chemical analysis. ALK-positive IMTs may have higher recurrence rates, while ALK-negative IMTs seem to occur in older patients and have higher metastatic rate (2,12). In our case, the tumor had two poor predictive factors, including the infiltrating characteristics at presentation and negativity for ALK; nevertheless, regression without surgical resection was observed. At 2 years follow-up the patient remains clinically well and with normal inflam-matory parameters.

Fig. 5. Follow-up pelvic magnetic resonance imaging 2 years after presentation. A. Axial T2-weighted image shows a resolution of the previously described tumor, with minimal thickening of the rectal wall. B. Sagittal T2-weighted image confirms the macroscopic resolution of the tumor.

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