ABSTRACT
PURPOSE: To report a case of intermediate grade meningeal melanocytoma presenting as a recurrent orbital mass. INTRODUCTION: Melanocytomas are rare, primary, pigmented tumors of the central nervous system, usually presenting as well-circumscribed, encapsulated, solid masses in the posterior cranial fossa and at the spinal region, often attached to the underlying dura. Orbital manifestation is rarely encountered. METHODS: Case report with computed tomography scan, magnetic resonance imaging, histology, and immunohistochemistry. RESULTS: A 40-year-old man presented with a recurrent orbital mass manifesting as progressive proptosis of the right eye of 4 years duration. The computed tomography scan and magnetic resonance imaging revealed an intraconal mass in the superior quadrant of the orbit. Histological analysis of the excision biopsy of the mass showed a highly cellular, locally infiltrating melanocytic neoplasm suggestive of an intermediate grade meningeal melanocytoma. Immunohistochemical staining for S-100 protein and HMB-45 monoclonal antibody confirmed the diagnosis. CONCLUSIONS: Recurrent intermediate grade orbital melanocytomas are rarely encountered and have to be distinguished from other topographically similar primary melanotic tumors. They have to be managed more aggressively if intracranial extension is present due to its close relation to the visual pathways.
Subject(s)
Nevus, Pigmented/pathology , Orbital Neoplasms/pathology , Adult , Antigens, Neoplasm/analysis , Biomarkers, Tumor/analysis , Humans , Magnetic Resonance Imaging , Male , Melanoma-Specific Antigens , Neoplasm Proteins/analysis , Neoplasm Recurrence, Local , Nevus, Pigmented/chemistry , Nevus, Pigmented/surgery , Orbital Neoplasms/chemistry , Orbital Neoplasms/surgery , S100 Proteins/analysis , Tomography, X-Ray Computed , Visual AcuityABSTRACT
Pilomyxoid astrocytomas is an uncommon aggressive piloid neoplasm, closely related to pilocytic astrocytomas and typically presents in the very young but can occur in older children and rarely in adults. A 12-years-old male presented with focal seizures, headache and vomiting of 10 days duration. Computed tomogram showed a hypo- to hyperdense and peripherally enhancing, solid-cystic lesion in the left temporal lobe. Histopathological examination revealed a characteristic tumor composed of bipolar cells arranged in dyscohesive sheets, angiocentric pattern in a loose myxoid background, with brisk mitotic activity and foci of necrosis. No Rosenthal fibers or eosinophilic granular bodies were seen. The tumor cells showed strong GFAP and scattered p53 positivity, but were negative for EMA. Ki-67 positivity ranged from 30 to 40%, highest reported till date. The patient was treated with radiotherapy and concurrent temozolamide and the tumor recurred after two years.