Pyogenic granuloma-like Kaposi sarcoma presenting in an HIV-negative man who has sex with men

Abstract

A 36-year-old immunocompetent man who have sex with men first presented to the plastics team with an ulcerating lesion on his left first toe. The lesion was suggestive of pyogenic granuloma (PG) clinically and histologically. Two years later, the same patient presented to the dermatology clinic with a new erythematous lesion with intermittent bleeding on the left second toe. Clinically, this lesion was suggestive of another PG. However, the histology of the skin curettage revealed part of a PG merging with an atypical spindle cell proliferation with characteristic 'sieve-like' appearance in keeping with Kaposi sarcoma. This was confirmed with human herpesvirus-8 immunohistochemistry staining. PG-like Kaposi sarcoma is an uncommon variant of Kaposi sarcoma. Often not considered clinically or histologically, a deep skin biopsy is essential to establish the right diagnosis. Our case highlights the need to consider Kaposi sarcoma as a differential diagnosis in all patients, including HIV-negative individuals, presenting with PG-like lesions.

Keywords: dermatology; infectious diseases; pathology; sexual health; skin cancer.