Diffuse cavernous haemangioma of the rectum (DCHR) is an uncommon vascular pathology usually diagnosed in younger patients (5-25 years old) with painless, recurrent rectal bleeding. Here, an unusual case of an older patient with sigmoid adenocarcinoma and concomitant diffuse DCHR from the rectum to the distal edge of the anal canal is reported.The purpose of this article is to report this unusual case and to discuss pitfalls in diagnosis, preoperative assessment and treatment of DCHR.