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|LETTER TO EDITOR
|Year : 2014 | Volume
| Issue : 6 | Page : 701-703
Supratentorial parenchymal CNS melanocytoma - Report of a rare case
Zarina Abdul Assis1, Ravi Dadlani2, Sunitha P Kumaran1, Nandita Ghosal3
1 Department of Radiology, Sri Sathya Sai Institute of Higher Medical Sciences, Bangalore, Karnataka, India
2 Department of Neurosurgery, Sri Sathya Sai Institute of Higher Medical Sciences, Bangalore, Karnataka, India
3 Department of Pathology, Sri Sathya Sai Institute of Higher Medical Sciences, Bangalore, Karnataka, India
|Date of Submission||06-May-2014|
|Date of Decision||04-Sep-2014|
|Date of Acceptance||05-Dec-2014|
|Date of Web Publication||16-Jan-2015|
Zarina Abdul Assis
Department of Radiology, Sri Sathya Sai Institute of Higher Medical Sciences, Bangalore, Karnataka
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Assis ZA, Dadlani R, Kumaran SP, Ghosal N. Supratentorial parenchymal CNS melanocytoma - Report of a rare case. Neurol India 2014;62:701-3
Primary central nervous system (CNS) melanocytoma is a benign pigmented tumor, accounting for less than 0.1% of brain tumors, almost always extra-axial in location with or without parenchymal invasion. Most of these tumors have dural attachment on imaging or intraoperatively.  We report this rare case of parenchymal melanocytoma with no dural attachment.
A 49-year-old lady presented with history of unilateral headache since 7 years and generalized tonic clonic seizures since 5 years. On examination, she had no neurological deficits. Magnetic resonance imaging (MRI) brain [Figure 1] demonstrated a well-defined T2 hypointense, T1 hyperintense cortex-based intra-axial lesion located at the left precentral gyrus with minimal perilesional edema. The lesion showed blooming artifact on gradient echo (GRE) images. There was no signal loss on fat saturated images. No dural attachment was demonstrated on MRI. Patient underwent left parietal craniotomy with complete excision of the lesion. Intraoperatively, the lesion showed blackish discoloration and was clearly located in intraparenchymal plane without any meningeal attachment [Figure 2]. Her postoperative course was uneventful. Histopathological examination revealed a tumor composed of polygonal, oval and spindle cells arranged in lobular pockets and focal fascicular pattern. The cells had showed vesicular nuclei with and prominent small, eosinophilic nucleoli in many. The cytoplasm of the cells showed coarse, granular, brownish black pigment [Figure 3]a, which on special stain (melanin bleach) got bleached [Figure 3]b. No necrosis was seen. Cells showed minimal nuclear pleomorphism with occasional mitotic figure (0-1/10 HPF). The tumor was immunonegative for epithelial membrane antigen (EMA) and S-100 protein, thus ruling out melanocytic meningioma and schwannoma, respectively. Features were compatible with melanocytoma.
|Figure 1: (a) T2W axial image showing a well - defined surface intra - axial hypointense lesion in the left frontal lobe with minimal perilesional edema. (b) T1 axial image shows the lesion as homogeneously hyperintense. (c) GRE axial image showing blooming artifact within the lesion. (d) No post - contrast enhancement appreciated on post - contrast T1 axial image|
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|Figure 2: An intra - operative image demonstrating the black colored, intra - parenchymal lesion in (a) white arrow. The image in (b) displays the operative bed after complete excision of the lesion. There was no attachment to the dura|
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|Figure 3: Paraffin section of melanocytoma showing (a) oval to spindle cells with dense granular blackish brown pigment in cytoplasm (straight arrow), arranged in lobules. (b) Melanin bleach showing absence of pigment. [Hematoxylin and eosin (a) ×400; Melanin bleach (b) ×400]|
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Whole spine MRI screening did not demonstrate any spinal melanocytic lesions. Ultrasonography of abdomen and pelvis was normal. The patient did not demonstrate any abnormal skin pigmentation. Since complete excision of the tumor was performed, no radiotherapy was advised. On 10 months follow up, patient was symptom-free and repeat MRI demonstrated no recurrence.
CNS melanotic tumors include diffuse melanocytosis and melanomatosis, melanocytoma, and malignant melanoma. These lesions arise from the leptomeningeal melanocytes derived from neural crest during embryonic development.  Melanocytomas of the CNS are rare pigmented benign tumors that occur in all age groups, with a preference for females. It was first described by Limas and Tio in 1972 and accounts for 0.06 − 0.1% of brain tumors.  Till date, only six cases of supratentorial CNS melanocytomas were reported in literature; , however, none in intraparenchymal location (as seen in the present case). MRI plays an important role in identifying melanin containing tumors, which are typically T1 hyperintense and T2 hypointense, explained by the presence of free paramagnetic radicals in the melanin, paramagnetic products of hemorrhage, and presence of fat. Meningeal melanocytomas are benign lesions with indolent growth without local invasiveness; however, there are reports of it being locally invasive and with postsurgical recurrence.  Based on the data concerning relevant cases available from the literature, complete tumor resection should be considered the best therapeutic option. In cases in which complete resection is not possible, postoperative radiation will be of benefit.  Supratentorial melanocytomas are relatively rare and their prognoses have not been specifically studied. Here, we present the 10-month follow-up data with no recurrence.
In conclusion, a T1 hyperintense, T2 hypointense lesion with blooming artifact on GRE should raise a suspicion for melanin containing lesion despite any location, presence, or absence of skin pigmentation. Complete excision is the treatment of choice. Partial resection warrants adjuvant radiotherapy as local recurrence is common.
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Brat DJ, Perry A. Melanocytoc lesions. In: Louis DN, Wiestler OD, Cavenee WK, editors. WHO Classification of Tumors of the Central Nervous System. 4 th
ed.. Lyon: IARC press; 2007. p. 181-3.
Gupta A, Ahmad FU, Sharma MC, Garg A, Mehta VS. Cerebellopontine angle meningeal melanocytoma: A rare tumor in an uncommon location. Case report. J Neurosurg 2007;106:1094-7.
Wang H, Zhang S, Wu C, Zhang Z, Qin T. Melanocytomas of the central nervous system: A clinicopathological and molecular study. Eur J Clin Invest 2013;43:809-15.
Lin B, Yang H, Qu L, Li Y, Yu J. Primary meningeal melanocytoma of the anterior cranial fossa: A case report and review of the literature. World J Surg Oncol 2012;10:135.
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[Figure 1], [Figure 2], [Figure 3]
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