Diffuse MOC-31 Expression in Hepatocellular Carcinoma: A Diagnostic Challenge

Introduction: Distinguishing hepatocellular carcinoma (HCC) from other primary liver tumors and metastatic carcinomas involving the liver can be problematic, especially in cases which do not exhibit classic hepatocellular morphology or immunohistochemistry (IHC). The clinical history including chronic viral infections, metabolic syndrome, alcohol, cirrhosis, and alpha-fetoprotein levels (AFP) can often help in this distinction. However, hepatoid adenocarcinoma (HAC), a rare but distinct entity, enters the list of differentials as it closely mimics HCC and may not be distinguished based on histology or immunohistochemistry. HAC is known to be aggressive and has limited therapeutic options; hence its distinction from HCC is crucial.