Superficial cervicovaginal myofibroblastoma: fourteen cases of a distinctive mesenchymal tumor arising from the specialized subepithelial stroma of the lower female genital tract.

The clinicopathologic features and immunohistochemical profiles of 14 cases of a distinctive mesenchymal tumor that arises in the superficial lamina propria of the cervix and vagina and is histologically distinguishable from mesodermal (fibroepithelial) stromal polyp, including the cellular (pseudosarcomatous) variant, angiomyofibroblastoma, aggressive angiomyxoma, and other well-recognized lesions that occur in this location, are described. The lesions presented as a polypoid (n = 10) or nodular (n = 4) mass in the vagina (n = 12) or cervix (n = 2) of women ranging in age from 40 to 74 years (median, 58 years). The tumors were subepithelial in location, were well circumscribed, and ranged in size from 1 to 6.5 cm. (mean, 2.7 cm). Microscopically, the process was moderately to highly cellular and composed of relatively bland spindled and stellate-shaped mesenchymal cells embedded in a finely collagenous stroma that was punctuated by myxoid and edematous foci in 9 cases. The lesions characteristically had a multipatterned architecture with tumor cells focally assuming a lacelike/sievelike growth pattern in the more stroma-rich areas of the tumor and a vague fascicular growth pattern in the more cellular foci. Mitotic activity was minimal, and no atypical mitotic figures were identified. The tumors were immunoreactive (in decreasing order of relative strength) for vimentin (5 of 5 cases), estrogen (10 of 10 cases), and progesterone (10 of 10 cases) receptors, desmin (13 of 13 cases), CD34 (11 of 13 cases), alpha-smooth muscle actin (5 of 11 cases), and muscle-specific actin (2 of 8 cases). The desmin and CD34 antibodies highlighted the interconnecting, dendritic processes associated with many of the tumor cells. No immunoreactivity was detected for S100 protein, epithelial membrane antigen, or keratins. Follow-up data for 11 patients (range, 1 to 20 years; median, 4 years) showed no recurrence or metastasis after local excision. The term "superficial cervicovaginal myofibroblastoma" is proposed because it reflects the distinguishing features of this benign, relatively site-specific mesenchymal tumor. The process probably arises as a neoplastic proliferation of hormonally responsive mesenchymal cells native to the unique subepithelial stromal layer normally found through the endocervix and vulva of adult women.