Cholecystic granulomas in gallstone disease. A clinicopathologic study of 17 cases.

This paper concerns with 17 cases of chronic cholecystitis with various granulomatous changes of the wall. All materials were obtained from patients who underwent cholecystectomy for various complications of gallstone disease. The only significant sign attributable to the granulomas was a palpable nodular induration in the wall at operation in several cases, and this led to a suspicion of neoplasm in one. Pathologically, these lesions were characterized principally by nodular proliferation (0.5-3.0 cm in size) of various forms of histiocytic cells, including lipid-containing histiocytes (foam cells), PAS positive brown pigmented cells, and multinucleated giant cells. Deposition of bile pigment and/or cholesterin crystals were found deeply in the areas of granulomatous reaction in about two-thirds of the cases. This finding supports a bile-induced granulomatous process of these lesions. The granuloma in one of our series contained typical Michaelis-Gutmann bodies seen in a case of malakoplakia. It is suggested that bile materials, which are capable of eliciting intense phagocytic reaction, may also act as an initiating factor in formation of malakoplakic lesions.