A 51-Year-Old Man Avoiding Sexual Intercourse Due to Rectal Pain

Editor's Note:
The Case Challenge series includes difficult-to-diagnose conditions, some of which are not frequently encountered by most clinicians but are nonetheless important to accurately recognize. Test your diagnostic and treatment skills using the following patient scenario and corresponding questions. If you have a case that you would like to suggest for a future Case Challenge, please contact us.

Background

A 51-year-old man with HIV infection, which is well controlled with antiretroviral medications, presents with rectal pain and intermittent episodes of hematochezia for 6 months. He also reports tenesmus and a recent 15 lb (6.8 kg) weight loss. He has not had fever, nausea, vomiting, constipation, or diarrhea. In addition, he has not noted any significant ulcerations in the oral, genital, or anorectal areas in recent months.

The patient has sex with men and prefers receptive anal intercourse. However, he has not been sexually active for the past 12 months because of cramping rectal pain.

For his HIV infection, he takes bictegravir/emtricitabine/tenofovir alafenamide. Other significant past medical history includes syphilis, for which he received treatment 6 months earlier. He does not use illicit drugs, smoke tobacco, or consume alcohol. His family history is notable for cancer of the left ovary in his mother and pancreatic cancer in his sister.