Metaplasia and precursor lesions of gallbladder carcinoma. Frequency, distribution, and probability of detection in routine histologic samples.

BACKGROUND

Gallbladder diseases, especially cholelithiasis, are extremely frequent in Chile, and an increasing frequency of gallbladder carcinoma has been observed during the last decades. Hyperplastic and atypical epithelial lesions of gallbladder epithelium have been considered potential precursors of invasive carcinoma. The current study was designed to study the frequency, distribution, extension, and probability of routine detection of potentially preneoplastic changes of gallbladder epithelium.

METHODS

Epithelial changes were histologically studied by mapping gallbladders obtained at elective cholecystectomy for lithiasis in 162 Chilean patients.

RESULTS

Antral-type metaplasia was found in 95.1% of the cases, intestinal metaplasia in 58.1%, hyperplasia in 46.9%, dysplasia in 16%, and carcinoma in situ in 2.5%. A significant association of intestinal metaplasia with hyperplasia, intestinal metaplasia with dysplasia, and hyperplasia with dysplasia was found. Hyperplasia and dysplasia were also present in four cases with carcinoma in situ. Mean extension of the lesions (percentages of the sections in which the change was observed) was antral-type metaplasia (62.7%), intestinal metaplasia (25.3%), hyperplasia (24.1%), dysplasia (15.5%), and carcinoma in situ (9.7%). Antral-type and intestinal metaplasia were more extensive and more severe in patients older than 50 years of age. Hyperplasia was more extensive in cases in which it was associated with dysplasia and carcinoma in situ.

CONCLUSIONS

The extension of metaplasia seems to depend in part on the age of the patients. The association of intestinal metaplasia with hyperplasia and dysplasia agrees with the findings of other authors that relate metaplasia to gallbladder cancer. The epithelial lesions are focal or partially confluent, thus a single random histologic section will detect less than one third of the hyperplasias, dysplasias, and carcinomas in situ.