Endocervical fibroblastic malignant peripheral nerve sheath tumor (neurofibrosarcoma): report of a novel entity possibly related to endocervical CD34 fibrocytes.

Primary cervical stromal sarcomas are rare neoplasms that have been poorly characterized. We report the clinical, histologic, and immunohistologic features of 3 primary endocervical S100 protein (S100p)-positive and CD34-positive sarcomas, herein designated as fibroblastic malignant peripheral nerve sheath sarcoma (endocervical neurofibrosarcoma), 2 of which occurred in women younger than 35 years of age. All tumors presented as a cervical polyp or mass lesion; 1 extended into the pelvic side wall and vaginal soft tissue. The tumors measured 2.0 to 8.0 cm, and were composed of compact fascicles of spindled cells arranged in herringbone, loose fascicular, or ill-defined storiform patterns. A focal whorled architecture was identified in all 3 tumors, but distinct Antoni A areas and Verocay bodies were absent. Ultrastructural examination in 1 case confirmed the presence of fibrocyte-like differentiation. Strong, diffuse, and in 1 case, patchy S100p expression was seen in all cases; strong and diffuse CD34 expression was also present in all tumors. Adjacent uninvolved endocervical stroma also showed CD34 positivity but expression was much less dramatic than in tumor cells. All other markers of neural, melanocytic, smooth muscle, endometrial stromal, and epithelial differentiation were negative. One of the tumors behaved extremely aggressively with extensive pelvic involvement, resulting in patient death within 16 months of diagnosis; another tumor was associated with pelvic recurrence 13 months after diagnosis; and the third tumor had an indolent course with no evidence of recurrence at 33 months after complete excision and local radiotherapy, although follow-up was limited. Review of large numbers of mesenchymal tumors in the uterus did not show similar tumors. Endocervical neurofibrosarcoma should be distinguished from solitary fibrous tumor, endometrial stromal sarcoma, leiomyosarcoma, melanoma, and other spindle cell neoplasms. The prominent fibroblastic endoneurial-like differentiation seen in this peripheral nerve sheath tumor may be related to the presence of a rich mucosal stromal fibrocyte network in the endocervix.