Primary Sclerosing Cholangitis, Small Duct Primary Sclerosing Cholangitis, IgG4-Related Sclerosing Cholangitis, and Ischemic Cholangiopathy: Diagnostic Challenges on Biopsy.

Pathologists face many challenges when diagnosing sclerosing biliary lesions on liver biopsy. First, histologic findings tend to be nonspecific with similar to identical features seen in numerous conditions, from benign to outright malignant. In addition, the patchy nature of many of these entities amplifies the inherent limitations of biopsy sampling. The end result often forces pathologists to issue descriptive sign outs that require careful clinical correlation; however, certain clinical, radiologic, and histologic features may be of diagnostic assistance. In this article, we review key elements of four sclerosing biliary processes whose proper identification has significant prognostic and therapeutic implications.