Seek and ye shall find: the importance of careful macroscopic examination and thorough sampling in 2522 cholecystectomy specimens

Gallbladder dysplasia and carcinoma (GBDC) vary greatly in incidence worldwide. We aimed to determine their prevalence in an Irish population, to assess the influence of tissue sampling protocols upon GBDC diagnosis, and to correlate various macroscopic and microscopic features with GBDC. We retrospectively reviewed histology reports of cholecystectomy specimens accessioned from 2000 to 2013. A total of 2522 cholecystectomy reports were reviewed, from 1860 female and 662 male patients. Male patients were significantly older (54.8 vs 46.8 years). There were 29 cases of dysplasia (1.15%) and 12 cases of carcinoma (0.48%), of which 10 were primary gallbladder cancers (0.4%). In 83.4% of cases, there was pathologic or radiologic evidence of cholelithiasis. Histologic findings included chronic (91.1%) or acute (15.4%) cholecystitis, cholesterosis (10.9%), adenomyomatous hyperplasia (2.1%), xanthogranulomatous inflammation (2.02%), and “porcelain” gallbladder (0.2%). Patients with GBDC were more likely to have a macroscopically identifiable lesion (29.4% vs 1.8%, positive predictive value, 18.18%, negative predictive value, 99.03%). Gallbladder dysplasia and carcinoma patients also had larger gallstones (median, 19 vs 12 mm) and were more likely to have adenomyomatous hyperplasia (8.8% vs 2.05%). When cases with a macroscopically identifiable lesion or clinical details suggestive of a gallbladder tumour were excluded (n = 2385), GBDC was significantly more frequently diagnosed if multiple tissue blocks had been sampled (2.91% vs 0.76%; relative risk (RR), 3.836). Rates of GBDC in Irish cholecystectomy specimens are low. The absence of a macroscopically identifiable lesion has a high (but not 100%) negative predictive value for GBDC. Sampling with more than 1 block significantly increases pickup rates of GBDC in these cases.