Fibroblastic Malignant Peripheral Nerve Sheath Tumour of the Uterine Cervix: Report of a Case and Literature Review With Emphasis on Possible Differential Diagnosis.

Cervical sarcomas are rare neoplasms, accounting for <1% of all cervical malignancies and characterized by an aggressive course despite radical excision. We report the clinical and microscopic features of a spindle cell sarcoma arising as a polypoid endocervical mass in a 45-yr-old woman. The neoplasm was characterized by a monotonous, mildly atypical proliferation of spindle cells, displaying a fibrosarcoma-like parallel pattern of highly dense fascicles, growing under the cervical epithelium. Mitotic activity was conspicuous, with up to 40 mitoses per 10 HPF. On immunohistochemistry, tumor cells were patchy S-100 protein positive. Additional immunohistochemical markers performed to rule out smooth muscle, melanocytic, epithelial, and sarcomatous differentiation were negative. A possible monophasic synovial sarcoma was also excluded by negative fluorescence in situ hybridization t(X;18) analysis. Interestingly, the neoplasm showed a focal CD34 positivity, as reported in normal fibrocytic cells of the endocervical stroma. Giving the morphologic and immunohistochemical features, the neoplasm was eventually defined as malignant peripheral nerve sheath tumor. Histologic examination following radical surgery revealed the neoplasm was confined to the uterine cervix (FIGO stage IB1) and at 12 mo of follow-up, the patient is still free of disease. Malignant peripheral nerve sheath tumors are highly aggressive sarcomas that can rarely involve the uterine cervix. They have to be differentiated from melanoma, leiomyosarcoma, endometrial stromal sarcoma, synovial sarcoma, and other spindle cell neoplasms.