A persistently recurring peri-urethral soft tissue lesion of the vulva

Various mesenchymal lesions, some of which have only recently been characterized, may affect the vulva. Because of their apparently shared origin from vulvovaginal mesenchyme, these lesions can resemble one another superficially and can be challenging diagnostically. Clinically, benign lesions and tumor-like conditions may mimic a malignant process because of hypercellularity, mitotic activity, and rapid growth. We report on a 84-year-old diabetic and hypertensive woman who had previously undergone skinning vulvectomy for lichen planus and an embolectomy of the left femoral artery. The patient presented with a rapidly growing vulvar mass. The biopsy showed spindle cell proliferation in a loose myxoid stroma with granulation tissue and a mixed inflammatory infiltrate. Based on histology and immunohistochemistry, the initial diagnosis was that of a benign lesion. In view of the persistent recurrence of the lesion and the absence of metastatic spread, we conclude that the lesion has a low-grade malignant potential and suggest the diagnosis of florid cellular reactive pseudosarcomatous myofibroblastic proliferation.