Hepatoid adenocarcinoma of the gallbladder with production of alpha-fetoprotein

Hepatoid adenocarcinoma (HAC) is a tumor with aberrant hepatocellular differentiation that occurs in extrahepatic organs. HAC of the gallbladder is rare, and cases of alpha-fetoprotein production are extremely rare. A 61-year-old man was diagnosed with gallbladder adenocarcinoma after laparoscopic cholecystectomy. A radical operation including resection of liver bed and lymph node dissection was performed, and no tumor cell was found. However, at postoperative 19 months, he showed lymphadenopathy of the portocaval area and tumor thrombi in the right portal vein with high levels of serum alpha-fetoprotein. After right hemihepatectomy and portahepatis lymph node dissection was performed, he was diagnosed with metastatic HAC. On reviewing the gallbladder specimen, the tumor finally demonstrated HAC as the primary origin. Despite adjuvant therapy, the patient died from multiple liver metastasis 26 months after cholecystectomy. Although HAC of the gallbladder is a very rare malignancy, awareness of its existence is critical to avoid misdiagnosis.