中枢神经系统脑脊膜黑色素细胞瘤三例及文献复习

Primary meningeal melanocytoma of the central nervous system： report of 3 cases with literature reviews

目的探讨中枢神经系统脑脊膜黑色素细胞瘤（PMM）临床及病理学特征。方法结合文献复习，回顾性分析3例中枢神经系统原发的脑脊膜黑色素细胞瘤。结果2例肿瘤位于椎管内，1例位于小脑脑桥角。肿瘤外观呈黑色，部分肿瘤包膜完整。光镜下见瘤细胞由上皮样细胞和梭形细胞混合而成，细胞无明显异型，核仁明显。大部分瘤细胞质内含有大量黑色素颗粒。例1、例3肿瘤核分裂像无或偶见（0～1个／10HPF），例2核分裂像较多（2～3个／10HPF）。免疫表型HMB45、MelanA和S-100蛋白呈阳性表达。例1、例2肿瘤完全切除，例3部分切除，随访均无复发。结论原发性脑脊膜黑色素细胞瘤是一种罕见的交界性或低度恶性肿瘤，具有一定的病理学特征，可局部复发或发生恶变，需要与原发或转移的恶性黑色素瘤、黑色紊性脑膜瘤及黑色紊性神经鞘瘤进行鉴别。

Objective To investigate the clinical and pathological features of central nervous system primary meningeal melanocytoma. Methods Combined with Chosen literature reviews, the clinical data of three patients suffering from central nervous system primary meningeal melanocytoma was analyzed. Results Two tumors were found in the leptomeninges of the spinal cord, while one was found in the cerebellopontine. Imaging studies revealed nodal lesions. Two tumors out of the three were encapsulated black masses. Histologically, epithelioid and spindle cells with abundant cytoplasms were arranged in loose nests. No cellular pleomorphism was seen and nucleoli were evidently. Fine melaningranules were the in the cytoplasm of tumor cells in all cases. The mitotic indexes for the two cases were zero or one per 10 HPFs and the index of one case was 2 - 3/10 HPF. lmmunnohistocbemieal studies of the tumors eonfilrmed the presence of HMB45, MelanA, and S - 100 proteins. The tumors in Case 1 and 2 were totally removed by operation,while the tumor in Case 2 was incompletely removed. No tumor reoccurred during the follow - up period. Conclusions Meningeal primary melanocytoma is a rare low - grade malignant tumor with certain pathology characteristics; the tumor may recur locally or transition to melanoma and should be distinguished from primary and melanoina melanomas, pigmented meningioma, and melanotic schwannoma.