Perianal mantle cell lymphoma mimicking an external thrombosed hemorrhoid: a case report.

Introduction: Malignancies of the anal margin and perianal skin are relatively uncommon, and account for approximately 2% to 3% of all anorectal malignancies. Despite the fact that gastrointestinal presentation of lymphoma is not uncommon, primary localization of mantle cell lymphoma to the perianal region is rare.

Case Presentation: We present the case of a 64-year-old Turkish man with a rapidly progressive perianal mass. Our patient had previously required medical treatment on multiple occasions for hemorrhoidal disease; however, the treatment was ineffective and gross lymph nodes were noted in his left inguinal region. Following excision of the mass and his lymph nodes, the pathological diagnosis of both tissues was mantle cell lymphoma.

Conclusion: Although gastrointestinal presentation of non-Hodgkin lymphoma is common, the literature includes only a few cases of perianal localization. Our case illustrates the importance of suspicion and complete examination of perianal masses. In practice, examination of the inguinal region should be a part of routine proctological examination.