A clear cell adenocarcinoma of the gallbladder with hepatoid differentiation: case report and review of literature.

An 80-year-old male was referred to our department for a gallbladder mass. He denied any history of alcohol consumption or cholecystitis and smoking. Hepatitis B surface antigen test and antihepatitis C antibody test were found to be negative. Serum carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen were elevated (CA19-9 was 59.92 U/mL and carcinoembryonic antigen was 12.64 ng/mL), whereas alpha-fetoprotein was below the normal limit (2.46 ng/mL). Computed tomography scan revealed a solid mass with measurements of 4.6×5.6×7.1 cm, which nearly filled the whole gallbladder space. Radical cholecystectomy, including segments IV B and V of the liver and lymphadenectomy, was performed. The neoplasm in gallbladder was completely resected, and the patient obtained a negative margin. Histological and immunohistochemical profile suggested a clear cell adenocarcinoma of the gallbladder with hepatoid differentiation. After reviewing the literature, we reported that this case is the first identified case of cell adenocarcinoma of the gallbladder with extensive hepatoid differentiation. However, clinical features of clear cell adenocarcinoma with hepatoid differentiation remain unclear due to the extremely rare incidence. There was no indication of adjuvant chemotherapy and no literature has been reported on the application of chemotherapy. This case showed a promising clinical outcome after curative resection, which indicated that surgical treatment could be potentially considered for suitable patients.