Meningioma associated with reactive hyperplasia and colonization of melanocytes

Abstract

Objective To summarize the clinical features, diagnosis and differential diagnosis of a case of meningioma associated with reactive hyperplasia and colonization of melanocytes. Methods and Results A 24⁃years⁃old female was discovered a left occipital lobe occupying occasionally by the head CT and MRI. The tumor revealed heterogeneous hyperintense and hypointense signals on T₁WI and heterogeneous isointense and hypointense signals on T₂WI with enhancement obviously. The left occipital lobe tumor was diagnosed clinically, and the left occipital posterior approach craniotomy was performed under general anesthesia. During operation, there was a smooth capsule on the surface of the tumor partially, which was dark in color and extremely rich in blood supply. Histological findings revealed the tumor cells were distributed in patches, and some of them were around blood vessels characterized by a prominent pseudopapillary architecture. Tumor cells were medium in size and eosinophilic cytoplasm was abundant. Giant tumor cells, intranuclear inclusion and scattered psammoma bodies were visible. A large number of pigmented cells consisted of dark, fine pigment granules. Immunohistochemical staining showed tumor cells expressed vimentin (Vim), E⁃cadherin, progesterone receptor (PR). Somatostatin receptor 2 (SSTR2), glial fibrillary acidic protein (GFAP), S⁃100 protein (S⁃100) presented partially positive. Melanosome⁃associated antigen (HMB45), Melan⁃A, epithelial membrane antigen (EMA), cytokeratin (CK), low molecular weight cytokeratin (LCK), high molecular weight cytokeratin (HCK), SOX10, L1⁃cell adhesion molecule (L1CAM), D2⁃40 and oligodendrocyte transcription factor⁃2 (Olig⁃2) were negative, but the pigmented cells were immunopositive for HMB45, SOX10. Genetic test revealed deletion of NF2 gene. The final diagnosis was meningioma associated with reactive hyperplasia and colonization of melanocytes. No chemoradiotherapy was performed after operation, and no recurrence of tumor was found by MRI. Conclusions Meningioma associated with reactive hyperplasia and colonization of melanocytes is a rare neoplasm. The diagnosis relies on its morphological characteristics, immunophenotype and genetic test. It should be differentiated from other tumors with melanocytes in the central nervous system.

doi：10.3969/j.issn.1672⁃6731.2021.06.011