Colonic diverticulitis-related exuberant granulomatous reaction in a patient with sarcoidosis.

A patient with long-standing sarcoidosis underwent partial colectomy for diverticular disease. Whereas sarcoid granulomas were rare in the otherwise normal colonic mucosa, an unusually large number of granulomas were scattered within the chronically inflamed peridiverticular tissues. It is suggested that in the framework of the sarcoidotic background, activated macrophages, being nonspecifically attracted to areas of inflammation, elicit an exuberant sarcoid granulomatous response. Our observation represents a previously undescribed variant of the "homing" phenomenon in sarcoidosis, unrelated insults inducing formation of granulomas in overabundance.