Lymphogranuloma Venereum Mimicking Locally Metastatic Rectal Cancer in an HIV-Negative Man.

Lymphogranuloma venereum (LGV) can present as a sexually transmitted anorectal syndrome and is caused by Chlamydia trachomatis serotypes L1, L2, and L3. It was rare in the western world until a recent outbreak among men who have sex with men (MSM) in Europe and North America. Limited availability of diagnostic tests differentiating LGV from non-LGV C. trachomatis can make the diagnosis challenging. We present a 33-year-old MSM with high-risk sexual behavior and anal atypical squamous cells of undetermined significance (ASCUS), who was evaluated for rectal pain, bleeding, constipation, and weight loss. Computed tomography of the abdomen and pelvis showed rectal wall thickening with pelvic adenopathy, concerning rectal carcinoma, also seen on colonoscopy as a 50% circumferential ulcerating rectal mass. The rectal swab was positive for C. trachomatis by immunofluorescence assay. Pathology confirmed severe active proctitis, but no malignancy. He was treated for presumed LGV proctitis with marked improvement. The case highlights an unusual presentation of LGV with severe inflammation and mass formation mimicking rectal carcinoma. Early identification of possible LGV especially in high-risk patients allows early appropriate treatment.