LAUSR

A 33-year-old, homosexual, sexually active man presented to the hospital with anal pain and hematochezia for >1 month. He had no signs of diarrhea or fever and no significant medical or pharmacotherapeutic history. Laboratory blood examination revealed increased white blood cell count (10,080; reference, 3300–8600/μL), C-reactive protein level (11.0; reference, 0.00–0.14 mg/mL), squamous cell carcinoma antigen (7.2; reference, 0–1.5 ng/mL), and HBs antigen (1067; reference, <0.005 IU/mL). Serum carcinoembryonic antigen (2.8; reference, 0–5 ng/mL), carbohydrate antigen 19-9 (17.3; reference, ≤37 U/mL), and cytomegalovirus antigenemia assay (C7-HRP) were all within reference ranges. No abnormalities were observed in the blood or fecal cultures. Computed tomography showed wall thickening from the left anus to the rectum. Colonoscopy showed a white-furred ileocecal valve, edematous and rough-surfaced mucosa throughout the entire colon, and an irregular and deep rectal ulcer (Fig. 1). Biopsy specimens were collected from every part of the colon and the ileocecal region. What is the diagnosis of a white-furred ulcerative lesion in the colon? BOOST YOUR LEARNING WITH QUIZ