Hepatic Epithelioid Hemangioendothelioma: Difficult Differential Diagnosis from Angiosarcoma.

Hepatic epithelioid hemangioendothelioma (EHE) is extremely rare, and preoperative diagnosis is difficult because hepatic EHE has clinicopathological features that are similar to those of angiosarcoma. However, it is important to differentiate hepatic EHE from angiosarcoma because the latter is an aggressive tumor with poor prognosis. We herein report a case of hepatic EHE that was difficult to distinguish from angiosarcoma by tumor biopsy. A 30-year-old man with Crohn's disease presented with multiple liver tumors. The tumors were preoperatively diagnosed as angiosarcoma by tumor biopsy. The patient underwent extended left hemihepatectomy with biliary reconstruction and partial resection of segments 6 and 8. Immunohistochemical staining was positive for CD34, factor VIII, and calmodulin binding transcription activator 1 (CAMTA1), and the pathological diagnosis was EHE. Two years after surgery, a recurrent tumor was found in liver segment 6, for which laparoscopic partial hepatectomy was performed. Pathological examination revealed recurrence of EHE. The patient remained well with no evidence of tumor recurrence as of 9 months after the second resection. In conclusion, we described a case of hepatic EHE that was initially diagnosed as angiosarcoma on biopsy. Immunohistochemical staining with CAMTA1 may help distinguish EHE from angiosarcoma.