We report herein two cases of carcinoma in situ of the gallbladder ass
ociated with cholesterosis. The patient in case 1 was an 81-year-old m
an who underwent a cholecystectomy for cholelithiasis. The resected sp
ecimens revealed gallbladder cancer in the fundus which was diagnosed
histologically as mucinous carcinoma. Other findings included 13-mm, 1
2-mm, and 5-mm polypoid lesions in the neck of the gallbladder which m
acroscopically appeared to be cholesterol polyps, but histologically d
emonstrated carcinoma in situ with cholesterosis. The patient in case
2 was a 76-year-old man in whom ultrasonography revealed a highly echo
genic, elevated lesion in the gallbladder. Cholecystectomy was perform
ed, and a 33 x 28-mm papillary, elevated lesion with cholesterosis was
resected from the neck of the gallbladder. Histologically, this was d
emonstrated to be papillary adenocarcinoma in situ with cholesterosis
surrounded by glandular dysplasia. The distribution of the carcinomas
and cholesterosis in both of these patients suggests that the adenoma
or carcinoma of the gallbladder had occurred first. Then, the tumor ep
ithelium absorbed cholesterol from the bile, and foamy cells were prod
uced. Thus, when treating cholesterol polyps, it should be remembered
that it is often difficult to distinguish between cholesterol polyp an
d gallbladder cancer with cholesterosis.