Abstract

Pleomorphic fibromas are rare, benign fibrous neoplasms classically described as cutaneous lesions of the trunk and extremities. Although fibroepithelial polyps are morphologically similar lesions affecting the vagina and vulva, no cases of pleomorphic fibromas involving the female genitourinary tract have been described in the literature to date. A 52-year-old, healthy female with normal menses and no contraceptive use presented with a 2-month history of an exophytic, skin-colored growth on the right labia minora. A shave biopsy of the lesion revealed a dermal proliferation of loose to densely arranged, variably spindled to epithelioid cells with stellate forms, admixed multinucleate cells, and hyperchromatic nuclei in a myxoid stroma. The dermal proliferation was nonreactive for S100, Melan-A, and SMA with insignificant CD34 reactivity on immunohistochemical studies. However, the cells of interest demonstrated scattered, strong positivity for Factor XIIIa throughout the lesion. The histologic and immunohistochemical features were consistent with a pleomorphic fibroma. This is the first reported case of a pleomorphic fibroma arising in the female genitalia, and it is morphologically comparable to its cutaneous counterpart despite the unconventional anatomic location. This case demonstrates the potential of this rare neoplasm to involve a previously undescribed site, thereby offering a novel contribution to the differential diagnosis for fibrous or stromal lesions of the female genitourinary tract.

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