Clinicopathologic characters of central nervous system primary melanocytic tumors

Abstract

Objective To investigate the central nervous system (CNS) primary melanocytic tumors (melanocytic tumors) and improve the understanding of melanocytic tumors. Methods and Results Since January 2012 to October 2019, 7 cases of melanocytic tumors were collected in Guangdong 999 Brain Hospital. Five patients underwent surgical resection and 2 patients underwent tissue biopsy. MRI showed high signal in T₁WI, low signal in T₂WI, and high signal in FLAIR. Tumor cell assumed a variety of shapes, including oval and polygonal, melanin⁃containing macrophages from benign to atypical. Results of immunohistochemistry showed that Melan⁃A and S⁃100 protion were consistently positive, and HMB⁃45 was negative, scattered or strongly positive. Four patients were diagnosed with meningeal melanocytoma, one with meningeal melanoma, one with diffuse meningeal melanocytosis, and one with meningeal melanomatosis. Four cases of melanocytoma underwent total or major resection, and of 3 cases received postoperative radiotherapy. The 2 cases who received radiotherapy were in good condition after follow⁃up of 56 and 116 months. The one case did not receive radiotherapy stay alive for 20 months. One meningeal melanomatosis patient received postoperative chemoradiotherapy, with a total survival time of 15 months. One patient with diffuse melanocytosis had a total survival time of 13 months. One meningeal melanocytosis patient improved after 7 months received chemoradiotherapy. Conclusions CNS primary melanocytic tumors are rare. Meningeal melanocytoma is common in the elderly, while diffuse meningeal melanocytosis is common in children. The expression patterns of melanin markers Melan ⁃A, S ⁃100 are consistently expressed, and HMB ⁃ 45 which helps to identify the benign and malignant tumors. The prognosis of tumour is still unclear. Melanocytoma has the best prognosis and benefits from radiotherapy.

doi：10.3969/j.issn.1672⁃6731.2021.08.010