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 p ropria of the cervix and vagina and is histologically distinguishable from mesodermal (fibroepithelial) stromal polyp, including the cellular (pseudos arcomatous) variant, angiomyofibroblastoma, aggressive angiomyxoma, and oth er 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 vag ina (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 ci rcumscribed, and ranged in size from 1 to 6.5 cm. (mean, 2.7 cm). Microscop ically, the process was moderately to highly cellular and composed of relat ively bland spindled and stellate-shaped mesenchymal cells embedded in a fi nely 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 th e 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 m itotic figures were identified. The tumors were immunoreactive (in decreasi ng 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 c ases), CD34 (11 of 13 cases), alpha-smooth muscle actin (5 of 11 cases), an d muscle-specific actin (2 of 8 cases). The desmin and CD34 antibodies high lighted the interconnecting, dendritic processes associated with many of th e tumor cells. No immunoreactivity was detected for S100 protein, epithelia l membrane antigen, or keratins. Follow-up data for 11 patients (range, I t o 20 years; median, 4 years) showed no recurrence or metastasis after local excision. The term "superficial cervicovaginal myofibroblastoma" is propos ed because it reflects the distinguishing features of this benign, relative ly site-specific mesenchymal tumor. The process probably arises as a neopla stic proliferation of hormonally responsive mesenchymal cells native to the unique subepithelial stromal layer normally found through the endocervix a nd vulva of adult women. HUM PATHOL 32:715-725. This is a US government wor k. There are no restrictions on its use.