Diffuse large B-cell lymphoma of the rectum in a patient with Crohn's disease.

A 62-year-old man presented to our institute with diarrhoea and dysuria on a background of subtotal colectomy and end ileostomy and biological therapy for Crohn's disease. He was diagnosed with urinary tract infection and acute kidney injury (AKI). Renal ultrasound suggested left hydronephrosis, with renal protocol computed tomography (CT) showing a large pelvic mass. Magnetic resonance imaging (MRI) of the pelvis demonstrated a rectal tumour invading the bladder and compressing both ureters. He underwent cystoscopy, flexible sigmoidoscopy and positron emission tomography-CT and was diagnosed with stage IV non-Hodgkin's diffuse large B-cell lymphoma. He was treated primarily with rituximab, cyclophosphamide, hydroxydaunomycin, oncovin and prednisolone chemotherapy regimen. He had ongoing urosepsis before admission for pelvic exenteration. He underwent cystoprostatectomy, excision of rectal stump and formation of ileal conduit. Histology showed no signs of residual malignancy. One year later, the patient was admitted to the intensive care unit with aspiration pneumonia, urosepsis and AKI. Despite maximal therapy, he developed multiorgan failure and passed away.