Summary

A 48-year-old man presented as an emergency with a 3-week history of rectal bleeding. Examination of his rectum revealed a circumferential tumour, 2 cm from the anal verge. An MRI scan reported a locally infiltrative mid-lower rectal tumour staged as T3d/T4 N2 MX. A colonoscopy revealed appearances of severe proctitis and biopsies did not show any evidence of dysplasia or malignancy. The patient was discussed at the regional colorectal cancer multidisciplinary team meeting with a management plan for neoadjuvant chemoradiotherapy following repeat biopsies, which were again negative for malignancy. He tested positive for the HIV and was referred to genitourinary medicine. A positive Chlamydia trachomatis nucleic acid test from a rectal swab was serovar L2 consistent with a diagnosis of lymphogranuloma venereum. He was treated with doxycycline and subsequent MRI scans showed reduction in tumour size with eventual resolution. This case report highlights the importance of HIV testing in patients with newly diagnosed colorectal tumours.