Vulvar hidradenoma papilliferum (HP) is located on the sites of mammary-like anogenital glands (MLAGs): Analysis of the photographs of 52 tumors

Background: Hidradenoma papilliferum (HP) is a benign tumor that primarily affects the anogenital area of adult women. Previously considered apocrine tumors, anogenital HP tumors are now interpreted as adenomas of mammary-like anogenital glands based on their histologic features. Objective: This clinical study was undertaken to determine whether vulvar HP is located on mammary-like anogenital gland sites and to describe its morphologic features. Methods: The clinical photographs of 52 histologically confirmed vulvar HP provided by 7 vulva specialists were analyzed. Results: In all, 90.4% of the HP were located on the interlabial sulcus, adjacent zone, or the perineum. These tumors were polymorphous in terms of number (1 or multiple), size (<1-4.5 cm), color (pink, red, blue), surface (ulcerated or not), and architecture (unilobular or multilobular). Limitations: Eight histologic reports could not be reviewed by the authors but the contributors confirmed that the photographs sent were only those of histologically confirmed HPs. Conclusions: Vulvar HP is mainly located on mammary-like anogenital gland sites, thereby providing further evidence to their histogenesis. Although a nonulcerated or ulcerated tumor of the interlabial sulcus should evoke a HP diagnosis, the latter must be confirmed histologically.