Vasculitis is an inflammatory process of the blood vessels, characterized by leukocyte infiltration in the vessel wall and reactive damage to the mural structures. They have a wide clinical spectrum and can present in a localized or systemic manner. Colonic involvement primarily manifests as abdominal pain and rectal bleeding. Less commonly, it can be associated with colonic perforation or anastomotic leakage after colorectal surgery. We report a case of a 42-year-old man with a history of HIV and proctocolitis who presented with an unexpected vasculitis of the sigmoid colon.