Aggressive angiomyxoma (AAM), a distinctive neoplasm occurring in the female perineum and pelvis, was initially described in 1983. Subsequently reported to occur in the inguinoscrotal region in men, this uncommon specialized genital stromal tumor is characterized by a paucicellular spindle cell proliferation separated by loose myxoid stroma with a prominent thick-walled, hyalinized vascular component. Despite the bland histologic appearance, AAM is an infiltrative tumor with a propensity for aggressive local and regional recurrences, especially when incompletely excised. Due to involvement of the deep pelvic soft tissues and retroperitoneal regions, these tumors often attain a large size and may not be amenable to complete surgical excision. While AAM can be very difficult to distinguish histologically from other myxoid soft tissue lesions of the vulvovaginal region, especially from the so-called benign angiomyofibroblastoma, differences in the clinical behavior between these various neoplasms require accurate diagnosis to ensure proper treatment. A variety of immunohistologic strategies have been proposed to be of value in differentiating these various tumors, but in many instances their relative contribution is overemphasized. In problematic cases, careful evaluation of a few key histologic features, in concert with attention to a series of practical considerations, including patient age, determination of adequacy of biopsy and tumor sectioning, tumor size, borders, and location (superficial versus deep), should permit accurate classification.