Angiomyofibroblastomalike tumor of the male genital tract - Analysis of 11 cases with comparison to female angiomyofibroblastoma and spindle cell lipoma

The clinicopathologic features and immunoprofile of 11 cases of an uncharacterized male genital tract tumor with features of vulvovaginal angiomyofibroblastoma (AMF) and spindle cell lipoma (male AMF-like tumor) are described. The lesions presented as a mass involving the scrotum (six cases) or inguinal region (five cases) in males ranging in age from 39 to 88 years (median 57). The tumors were superficially located and well-marginated and ranged in size from 2.5 to 14 cm (approximate mean 7 cm). Microscopically, they were composed of tapered spindled cells proliferating between numerous small to medium-sized vessels. Epithelioid appearing stromal cells were a focal finding in four cases. Mitotic activity was minimal with no abnormal mitotic figures identified. Mild nuclear atypia was identified in two cases. The tumors possessed an acid mucopolysaccharide-rich, finely collagenous stroma. A small quantity of intralesional fat was present in six cases. Tumor cells exhibited immunoreactivity for vimentin (seven of seven cases), progesterone receptor protein (five of seven cases), CD34 (four of eight cases), estrogen receptor protein (three of seven cases), desmin (three of eight cases), muscle-specific actin (three of eight cases), and smooth-muscle actin (two of eight cases) but not for S-100 protein, One of seven patients with follow-up after simple excision had recurrent/persistent disease. The male AMF-like tumor is a soft-tissue neoplasm of the male genital tract that shares clinicopathologic features and a proposed perivascular stem cell derivation with both the female angiomyofibroblastoma and spindle cell lipoma.