Microscopic adenoma in nonpolyposis coli: incidence and relation to basal cells and lymphoid follicles.

Six microscopic adenomas found in four patients of nonpolyposis coli (namely, not included in the group of familial polyposis coli) which had been detectable microscopically but not macroscopically, were examined by preparing complete serial section. With respect to the histogenesis of large-intestinal adenomas in nonpolyposis coli, they are considered to originate from the basal cells. As the background for this, a great number of adenomatous changes in basal cells were seen, and the microscopic adenomas showed a tendency of multiplicity (in the present study a total of 36 microscopic adenomas were detected). The above-described adenomatous changes in basal cells and development of microscopic adenomas are considered to be closely related to lymphoid follicles on the muscularis mucosa, with 20 (55.6 per cent) of 36 microscopic adenomas originating in the basal cell upon the lymphoid follicles.