A case of successful treatment with lenvatinib in primary hepatoid adenocarcinoma of the gallbladder that was difficult to distinguish from hepatocellular carcinoma.

Hepatoid adenocarcinoma (HAC) is an adenocarcinoma with components similar to those of hepatocellular carcinoma. Primary HAC of the gallbladder is extremely rare; to our knowledge, there is no consensus on the treatment after diagnosis. We reported an 82-year-old Japanese female of primary HAC of the gallbladder with postoperative recurrence that responded to lenvatinib. A total of 9 months has passed since the start of chemotherapy with lenvatinib, and the patient is in good general condition. To establish an effective treatment for primary HAC of the gallbladder, further accumulation and investigation of cases are recommended.