Solitary fibrous tumor of the uterine cervix.

A 68-year-old woman with stage pT1b1 N0 cervical squamous carcinoma had an incidental cervical polyp. The polyp measured 1.7 cm in maximal diameter and histologic evaluation showed it to be composed of spindle-shaped cells with hypercellular and hypocellular foci. The stroma was collagenized and contained several dilated vascular channels that imparted a hemangiopericytic pattern to the lesion. Immunohistochemistry showed the spindle cells to be positive for vimentin, CD99, CD34, bcl-2, ER, PR, and beta-catenin (cytoplasmic) but negative for EMA, S100, factor XIIIa, AE1/AE3, caldesmon, desmin, CD31, and smooth muscle actin. The morphology and immunophenotype was in keeping with a diagnosis of a solitary fibrous tumor (SFT). SFT shares several histologic features of a superficial cervicovaginal myofibroblastoma; the cellular variability, pattern and distribution of vessels, stromal collagenization, and desmin negativity favors SFT.