[Histologic and mucin histochemistry studies on the topic of so-called transitional mucosa in the vicinity of large intestine cancers].

Morphological analysis of the mucosal change of the large bowel called "transitional mucosa"; 38 resection specimens with colonic carcinoma and 14 specimens with non malignant changes for control were studied. The "transitional mucosa" is described as the sum of histological, cytological and mucin histochemical findings forming a characteristic mucosal pattern in the vicinity of the carcinomatous lesion in all cases but in one. However, the expression of the single morphological finding is variable and all characteristics of the mucosal alteration were also found frequently in the control group without malignant tumours. Therefore the diagnostic value of the "transitional mucosa" for early recognition of large bowel carcinoma is negligible. The pathogenesis of this lesion remains unclear but is discussed as a reactive hyperplasia of the mucosal crypts caused by a change of the large bowel contents initiated probably by a long-standing motility disturbance.