Clear cell adenocarcinoma of the gallbladder: A rare subtype of gallbladder carcinoma

Clear cell adenocarcinoma is a rare histologic subtype of gallbladder carcinoma. The tumor shows histologic similarities with metastatic tumors with clear cytoplasm. Therefore, metastatic clear cell renal cell carcinoma and clear cell carcinoma of the ovary and endometrium need to be excluded, especially when a precursor lesion or admixed conventional biliary adenocarcinoma is not found. When the tumor shows hepatoid differentiation, hepatocellular carcinoma should also be excluded. Moreover, a subset of clear cell adenocarcinoma can produce alpha fetoprotein (AFP) and may compound the diagnosis. The risk factors and clinical presentations of this subtype appear to be comparable to those in conventional biliary-type adenocarcinoma. It is unknown whether this histologic subtype impacts prognosis, probably due to its rarity. Herein, we review the clinical and pathologic features of clear cell adenocarcinoma of the gallbladder