[Morphology and morphogenesis of rectal cancer]

A review of the literature data and examination of 947 patients with rectal tumors point to the following factors of morphogenesis of rectal cancer: (a) polyps and polyposis--in approximately 10% of cases, (b) nonspecific ulcerative colitis and ulcerative lesions of mucosa--1-2% of cases, and (c) in 85% of cases, the genesis of rectal tumors was not clear. In the latter group, precancerous changes in rectal mucosa could not be identified.