Melanotic Schwannoma of Adrenal Gland - A Rare Entity/Diagnostic Dilemma

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Case Report

Melanotic schwannoma of adrenal gland e A rare entity/diagnostic dilemma

Feroz Amir Zafar a, Ishfaque A. Geelani a, Pravin Govardhane a, H. Girish a,D.V.S.L.N. Sharma a, V. Rajagopal a,*, Meenakshi Swain b, G. Swarnalatha b

aDepartment of Urology, Apollo Hospitals, Hyderabad, IndiabDepartment of Histopathology, Apollo Hospitals, Hyderabad, India

a r t i c l e i n f o

Article history:

Received 31 January 2013

Accepted 2 February 2013

Available online 9 February 2013

Keywords:

Melanotic schwannoma

Melanoma

Nerve sheath tumor

Adrenal schwannoma

* Corresponding author.E-mail address: raja_urol@rediffmail.com

0976-0016/$ e see front matter Copyright ªhttp://dx.doi.org/10.1016/j.apme.2013.02.001

a b s t r a c t

Introduction and objective: Melanotic schwannoma of adrenal gland is very rare entity with

only two series and less than 100 cases reported in literature. We report a case of melanotic

schwannoma.

Case report: A 62 years old man, a resident of Tanzania presented with 6 months history of

lower urinary tract symptoms (LUTS) for which he was evaluated and a right adrenal mass

detected incidentally on ultrasound.

He is known case of hypertension and hypothyroidism for which he is taking regular

medications. On general examination pulse was 80/min, regular and BP was130/80 mm of

Hg. Abdominal examination was unremarkable. MDCT examination revealed a right ad-

renal mass (4 � 4.8 cm) showing mild enhancement post contrast study with central area of

relatively less enhancement showing no significant contrast washout on delayed study.

The provisional diagnosis was ? pheochromocytoma, ? malignant. Functional study was

found to be normal. Laparoscopic exploration was done and mass excised. Gross patho-

logical examination showed a single globular circumscribed soft tissue mass measuring

4.5 � 4 � 3 cm and weighing 50 g with a nodular surface. The cut surface was black with

a central golden brown area measuring around 2.2 � 1.8 cm.

A diagnosis of malignant melanoma was considered, however in view of circum-

scription bland nuclei, absent of nucleoli, very few mitoses and presence of nerve fascicles;

a diagnosis of melanotic schwannoma was favored. The patient was advised regular fol-

low-up.

Conclusion: Melanotic schwannoma of adrenal is a very rare entity and every effort should

be made to rule out melanoma.

Copyright ª 2013, Indraprastha Medical Corporation Ltd. All rights reserved.

1. Introduction retroperitoneal tumors.1,2 They are circumscribed but unen-

Melanotic schwannoma of the adrenals is a rare, accounting

for only 1e3% of all schwannomas and only 1% of all

(V. Rajagopal).2013, Indraprastha Medic

capsulated, grossly pigmented tumor, composed of cells

having the ultra structure and immunophenotype of Schwann

cells that contain melanosomes and are reactive for

al Corporation Ltd. All rights reserved.

Fig. 1 e CECT of abdomen & pelvis (coronal, saggital &

transverse planes) showing the right adrenal mass (white

arrow).

Fig. 2 e CECT of abdomen & pelvis (coronal, saggital &

transverse planes) showing the right adrenal mass (white

arrow).

Fig. 3 e CECT of abdomen & pelvis (coronal, saggital &

transverse planes) showing the right adrenal mass (white

arrow).

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melanomamarkers. Cytological atypia is not uncommon. The

vast majority of non-psammomatous tumors affect spinal

nerves and paraspinal ganglia, whereas the psammomatous

lesions also involve autonomic nerves of viscera, such as the

intestinal tract, adrenal and heart. About 50% of patients with

psammomatous melanotic schwannoma have the rare

inherited autosomal-dominant disorder Carney complex type

Fig. 4 e Laparoscopic views of the darkly pigmented tumor

(yellow arrow).

Fig. 5 e Laparoscopic views of the darkly pigmented tumor

(yellow arrow).

Fig. 7 e Cut section of the tumor (heterogeneous).

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I (CNC) characterized by facial pigmentation, Cardiac myx-

oma, and endocrine overactivity. A correct preoperative

diagnosis is difficult to make and these tumors are often

misdiagnosed as other soft tissue lesions occurring in the

retroperitoneum.

Over 80 cases of one or more tumors have been reported in

literature so far.3 We describe a case of melanotic schwan-

noma of the adrenal gland.

2. Case presentation

Sixty two years gentleman, resident of Tanzania presented

with h/o lower urinary tract symptoms (LUTS) since >6

months and an incidentally detected right adrenal mass. He

gave a past history of hypertension and hypothyroidism

Fig. 6 e Resected specimen (pigmented).

which was under control with medications. On clinical ex-

amination, pulse e 80/min, BP e 130/80 mm of Hg. General

examination e No pallor/icterus/cyanosis/clubbing/edema

feet. P/A e soft, non-tender, no mass was palpable. In-

vestigations revealed Hb-12 g%, TLC-4100/mm,3 S. creatinine

e 1.2 mg%, RBS e 74 mg%, Metanephrines (24 h urine) e

1.0 mg/day, VMA (24 h urine) e 8.7/day, S. cortisol (dex-

amethasone suppression test) e 0.56 mg/dl. CT scan (Figs. 1e3)

showed a right adrenal mass (4 � 4.8 cm) showing mild

enhancement post contrast study with central area of rela-

tively less enhancement showing no significant contrast wash

out on delayed study (? pheochromocytoma/? malignant).

At Laparoscopic exploration, a heterogeneous, darkly pig-

mented (almost black) unencapsulated neoplasm was found

in the right retroperitoneal space, medially displacing the

inferior vena cava and clearly separated from the kidney and

the renal vein, which are pushed downward. The tumor was

completely excised (Figs. 4 and 5).

The specimen was sent for histopathological examination.

Fig. 8 e Low power 103 H&E stain.

Fig. 9 e 203 showing tumor attached to nerve fascicles.

Fig. 11 e Immunohistochemistry showing positive S 100.

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2.1. Gross description

Single globular circumscribed soft tissue measuring

4.5 � 4 � 3 cm & weighing 50 g. External surface was nodular

(Fig. 6). Cut surfacewas blackwith a central golden brown area

measuring around 2.2 � 1.8 cm (Fig. 7).

2.2. Microscopically

Lobules and nests of tumor cells with large areas of necrosis

and hemorrhage. The tumor cells are spindle shaped and ar-

ranged in intersecting fascicles. Tumor cells have moderate ill

defined fibrillary cytoplasm and have elongated bland vesic-

ular nuclei with few showing nuclear grooves (Fig. 8).

Abundant brownish black pigment is seen with in tumor

cells and also within the histiocytes (Fig. 10). Few mitoses

were seen averaging 1e2/10 hpf. Prominent nuclei typical of

melanoma are not seen. Perl’s stain is positive in the pigment

in hemosiderin laden macrophages and negative in pigment

in tumor cells (Fig. 11). A few nerve fascicles are seen at the

periphery adherent to the tumor (Fig. 9).

Fig. 10 e H&E (403) e Spindle cells running in fascicles with

intracytoplasmic melanin pigment.

3. Discussion

Melanotic schwannomas (MS) were first described in 1932 by

Millar.4 These tumors are rare, with approximately 80 cases

reported in the literature to date.3

Melanotic schwannomas are of neural crest origin proba-

bly caused by the neoplastic proliferation of a common pre-

cursor cell for both Schwann cells and melanocytes.5,6

Schwannoma is a neurogenic tumor usually arising between

the third and sixth decades of life, with an equal predilection

for men and women. It may occur in any organ or nerve trunk

with the exception of cranial nerves I and II, which lack

Schwann cells A preoperative diagnosis is very difficult to

make because of the lack of typical imaging features (US, CT

and MRI) that distinguish schwannomas from retroperitoneal

malignancies.7 Even with accurate preoperative imaging and

intraoperative frozen section analysis, the presence of a pos-

sible malignancy cannot be excluded, so a definitive diagnosis

can be obtained only through careful histological and immu-

nohistochemical examination. Surgical excision is considered

the treatment of choice for these tumors, which respond

poorly to radiation and chemotherapy.8 We were unable to

make a correct preoperative diagnosis. The following differ-

ential diagnosis was considered: malignant melanoma, mel-

anotic schwannoma, pigmented pheochromocytoma and

leiomyosarcoma. There was a diagnostic dilemma and ma-

lignantmelanomawas strongly considered, however in a view

of the circumscription, bland nuclei, absence of nucleoli, very

fewmitoses and the presence of nerve fascicles, a diagnosis of

a melanotic schwannoma was finally favored.

4. Conclusion

Melanotic schwannoma is a rare variant of schwannoma

composed of melanin-producing cells with ultrastructural

features of Schwann cells. Distinguishing between this tumor

and malignant melanoma is important in planning manage-

ment. Total resection should be performed. Appropriate long-

term follow-up is needed for all melanotic schwannomas.

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Conflicts of interest

All authors have none to declare.

r e f e r e n c e s

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3. Zhang HY, Yang GH, Chen HJ, et al. Clinicopathological,immunohistochemical, and ultrastructural study of 13 cases of

melanotic schwannoma. Chin Med J (Engl).2005;118(17):1451e1461.

4. Millar W. Malignant melanotic tumor of the ganglion cellsarising from the thoracic sympathetic ganglion. J Pathol.1932;35:351e357.

5. Vallat-Decouvelaere A-V, Wassef M, Lot G, et al. Spinalmelanotic schwannoma: a tumour with poor prognosis.Histopathology. 1999;35:558e566.

6. Watson JC, Stratakis CA, Bryant-Greenwood PK, et al.Neurosurgical implications of Carney complex. J Neurosurg.2000;92:413e418.

7. Hughes MJ, Thomas JM, Fisher C, Moskovic EC. Imagingfeatures of retroperitoneal and pelvic schwannomas. ClinRadiol. 2005;60:886e893.

8. Daneshmand S, Youssefzadeh D, Chamie K, et al. Benignretroperitoneal schwannoma: a case series and review of theliterature. Urology. 2003;62:993e997.

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