Isolated Lesion of Penile Kaposi Sarcoma in an HIV-Negative Male Patient.

Kaposi sarcoma (KS) is a vascular neoplasm commonly associated with HIV positivity and immunocompromise. A subtype of KS has been more recently described in HIV-negative men who have sex with men (MSM). We report a case of a patient presenting with a solitary lesion on the penis, which was diagnosed to be KS. The patient was a 43-year-old male with a previous history of treatment with valacyclovir for herpes simplex virus 1 (HSV-1) who tested negative for multiple sexually transmitted infections, including HIV. Diagnosis of KS was confirmed through histopathology of a skin punch biopsy. While KS is mostly associated with HIV-positive and immunosuppressed patients, it is important to note that anyone who has been infected with human herpesvirus 8 (HHV-8), usually transmitted through bodily fluids, can develop KS. MSM may statistically be at higher risk for developing KS, even without HIV-positive status. Prompt diagnosis is important in guiding clinical management in these patients.