Perianal abscess is a common condition treated surgically with early incision and drainage. It is commonly associated with bowel flora and less often with skin flora. However, in individuals with history of receptive anal intercourse, sexually transmitted infections like gonorrhea should also be considered. We report a case of a 46-year-old HIV-positive homosexual man who presented with features of a perianal abscess. However, no organisms were obtained on cultures. Instead, tissue biopsy revealed plasmablastic lymphoma-a very rare and highly aggressive variant of non-Hodgkin lymphoma. The unique features in our patient were the very unusual presentation in the form of acute perianal swelling mimicking an abscess and the absence of advanced HIV disease (his CD4 count was 973 cells/μL).
In HIV-positive individuals presenting with features of perianal abscesses, the differential diagnosis should be expanded to include not only sexually transmitted infections but also malignancies like lymphoma.