Benign anal and perianal polypoid neoplasms and tumor-like lesions

Abstract

Mesenchymal anal and perianal tumors are relatively uncommon. The majority are malignant. Benign mesenchymal anal tumors are rare. Some are common stromal neoplasms, but with the rare presentation as anal polyps. Other lesions are rare, but unique to the anal/perianal region. Common keratinous cysts might uncommonly present as anal polyps, while other rare cysts are unique to the anogenital region. A retrospective review study of 493 anal and perianal specimens conducted over seven years showed twenty cases (4.0%) of benign anal polypoid lesions. We excluded the usual fibroepithelial polyps, anal tags, papilla, hemorrhoids and warts. We found six cysts, three lipomas, two papillary hidradenomas, two melanocytic nevi, one hamartoma, one xanthogranuloma, one seborrheic keratosis, one hematoma, one fibrous histiocytoma, one granular cell tumor and one lymphangioma. The male to female ratio was 1.5:1. They were found in adults (mean age 37.8 years) and in infants (mean age 2.4 years). In general, they were smaller than 2 cm. They were either asymptomatic or presented with anal pain, bleeding or lumps. Some were clinically confused with the more common non-neoplastic anal tags, hemorrhoids and fibroepithelial polyps/papilla. A variety of common and rare benign lesions might present as anal polyps with important surgical and pathologic challenges and implications.