INCIDENCE AND PATHOGENESIS OF VILLOUS TUMORS OF THE GALLBLADDER, AND THEIR RELATION TO CANCER

The aim of this study was to investigate the incidence and pathogenesi s of villous tumors of the gallbladder, and their relation to cancer. Five hundred and thirty-three cases of cholecystectomy and 1300 random ly selected autopsy cases, mainly elderly individuals, were investigat ed. Gallbladders were fixed in 10% formalin after operation or at auto psy, followed by macroscopic study. In cases of villous tumors, the en tire gallbladder was cut into 5-mm-thick serial sections, embedded in paraffin, cut to 4-mum, stained with hematoxylin and eosin (H&E), and histologically studied. To investigate cancer-associated antigens, i.e ., carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 19-9, deparaffinized sections were examined by the peroxidase-antiperoxidase (PAP) immunohistochemical technique with anti-CEA and anti-CA 19-9 an tibodies. Villous tumor was found in two resected cases (0.38%) and in one autopsy case (0.08%). Histologically, one of the villous tumors c onsisted mainly of a proliferation of lining epithelia; the other two consisted mainly of a proliferation of glands. In all three cases, the patients had had accompanying chronic or acute inflammation and two w ere accompanied by cholecystolithiasis, which made us aware of the imp ortance of inflammation or trauma from stones in the pathogenesis of s uch neoplasms. Although no apparent cancerous epithelium was observed in any of these tumors by studying H&E specimens, moderate structural and cellular atypism was found in one of them. The atypical epithelium in this case was positively stained for CEA and CA 19-9. It was concl uded that villous tumor should be considered to be a premalignant lesi on.