Perianal Hidradenoma Papilliferum Mimicking a Chronic Hemorrhoid: A Case Report.

Hidradenoma papilliferum (HP) is a rare, benign neoplasm classically originating from apocrine or mammary-like glands. While predominantly presenting in the vulvar region, its occurrence in the perianal location is exceptionally rare and frequently misdiagnosed as hemorrhoidal disease or other localized benign lesions. We present the case of a 50-year-old female patient reporting acute perianal pain following defecation straining, accompanied by the sensation of an asymptomatic perianal mass present for three years. Clinical examination identified a 1.5 cm well-circumscribed, reddish-brown nodule at the anal verge. Excisional biopsy was performed under local anesthesia with 1 cm margins, allowing the wound to heal by secondary intention. Histopathological evaluation confirmed perianal HP, characterized by an arboriform papillary architecture, a double-layered epithelium, and classic apocrine decapitation secretion without cytological atypia. Complete surgical excision remains the definitive, curative treatment. This case highlights the absolute necessity of histopathological evaluation for atypical, therapy-resistant perianal lesions to avoid diagnostic anchoring and to definitively rule out malignancy.