Clinicopathological study of pituicytoma and its rare ependymal variant / 临床与实验病理学杂志

ABSTRACT

Purpose To study the clinicopathological, immunophynotypic features of pituicytoma and its rare ependymal variant with discussion of its diagnosis and differential diagnosis. Methods 7 cases of pituicytoma, including 6 conventional pituicytomas and 1 ependymal variant tumor, were evaluated by HE staining and immunohistochemistry, and the relevant literatures were reviewed. Results Microscopically, the tumors were composed of closely packed plump spindle cells arranged in short fascicle and storiform pattern in 6 conventional pituicytomas, and whorl and papillary architecture with obvious perivascular rosette formation in the ependymal variant tumor. Immunohistochemically, all tumor cells were diffuse positive for S-100 and TTF-1, but negative for IDH1 R132H, Olig-2, CD34, NF, Syn, CgA, and pituitary hormones. Ki-67 proliferation index was less than 2％ in all cases. GFAP and EMA were only focally positive in conventional pituicytomas, whereas GFAP was diffuse positive in ependymal variant tumor with EMA dot-like staining in more than half of tumor cells. Conclusion Pituicytoma is a rare low grade glioma derived from neurohypophysis. To study helps recognition of extending morphological spectrum of pituicytoma and its new variant, which is important for its differential diagnosis consideration and clinical therapy.