Ng W K, Khoo U S, Ip P, Collins R J
Department of Pathology, Pamela Youde Nethersole Eastern Hospital, Chai Wan, Hong Kong.
Acta Cytol. 1998 Jul-Aug;42(4):1022-6. doi: 10.1159/000331952.
Myxopapillary ependymoma is a variant of ependymoma that usually occurs in the sacrococcygeal region. Histologically, it is characterized by arborizing papillary fronds of capillaries with mucinous stroma rimmed by ependymal cells. The fine needle aspiration cytology of this rare tumor is rarely described in the literature.
We report the fine needle aspiration cytology of a primary sacrococcygeal myxopapillary ependymoma occurring in a 18-year-old female. Cytology showed "fernlike" papillae and globules of mucinous and myxoid substance containing central capillaries. These structures were rimmed by one to several layers of mitotically inactive, mildly pleomorphic cuboidal to columnar cells with occasional pseudonuclear cytoplasmic inclusions. Some of these ependymal cells sent fibrillary processes toward the capillaries, suggestive of perivascular pseudorosettes. There were also numerous isolated tumor cells in the background.
Because of the prominent mucinous elements and papillary fronds, myxopapillary ependymoma may mimic other myxoid or papillary tumors cytologically. Recognition of the characteristic cytologic features may allow a distinction to be made on fine needle aspiration biopsy.
黏液乳头型室管膜瘤是室管膜瘤的一种变异型，通常发生于骶尾部。组织学上，其特征为毛细血管呈树枝状分支的乳头样结构，伴有黏液样间质，周围被室管膜细胞包绕。关于这种罕见肿瘤的细针穿刺细胞学检查在文献中鲜有描述。
我们报告了1例发生于18岁女性的原发性骶尾部黏液乳头型室管膜瘤的细针穿刺细胞学检查结果。细胞学显示“蕨样”乳头以及含有中央毛细血管的黏液样和类黏液物质小球。这些结构被1至数层有丝分裂不活跃、轻度异形的立方状至柱状细胞包绕，偶尔可见假核性胞质内包涵体。部分室管膜细胞向毛细血管发出纤维状突起，提示血管周围假菊形团形成。背景中还可见大量散在的肿瘤细胞。
由于黏液成分和乳头样结构突出，黏液乳头型室管膜瘤在细胞学上可能会与其他黏液样或乳头样肿瘤相混淆。认识其特征性的细胞学表现有助于在细针穿刺活检时做出鉴别诊断。
