65 year old man with constipation associated with bleeding per rectum after defaecation and loss of weight for 6 months.
The colon shows a circumferential (napkin ring) pale, fleshy growth involving the full thickness of the bowel wall. The tumour is ulcerated with everted and nodular overhanging edges. The ulcerated base show necrotic slough. There is invasion of the serosal fat and possible perforation.