Approach to the diagnosis of dysplasia in the gallbladder

Abstract

Gallbladder is one of the more commonly removed organs with 1 million cholecystectomies performed annually in the US. Epithelial atypia with the differential diagnosis of reactive vs dysplasia vs carcinoma is not uncommon and is notoriously challenging. Recently, improved criteria were established for this differential through international consensus meetings, and sampling protocols have been put forth. In high GBC-risk regions, or high-risk patients like hyalinising/porcelain GB or PSC or pancreatobiliary maljunction, any atypia warrants careful attention and extensive sampling. In low risk situations, if atypia with suspicion of low-grade dysplasia (LGD) is encountered, 4 additional blocks are recommended, and in the absence of convincing HGD, no additional action is required; LGD by itself is regarded clinically inconsequential except for heralding HGD. HGD is often extensive by the time of diagnosis, involving most of the preserved mucosa (‘wild-fire phenomenon’) and shows severe atypia that is typically recognisable even in low power examination. HGD [aka CIS, or early gallbladder cancer (EGBC) due to the difficulty in distinguishing Tis from T1a/b] is curable disease provided that T2 (perimuscular) invasive carcinoma is carefully ruled out by total sampling. It is recommended that a case not be classified as HGD/CIS/EGBC if the GB has not been examined in toto.