Hepatic Epithelioid Hemangioendothelioma Presenting Synchronously with Hepatocellular Carcinoma

Hepatic epithelioid hemangioendothelioma (EHE) is a rare malignant tumor with unknown pathogenesis. Herein, we report a case of a hepatic EHE presenting synchronously with a hepatocellular carcinoma (HCC). To the best of our knowledge, this is the second case report of synchronous hepatic EHE and HCC. An 84-year-old man presented with back pain. During examination, a tumor in liver segment 3 was coincidentally detected. Tumor marker (carbohydrate antigen 19-9, alpha-fetoprotein, and protein induced by vitamin K absence or antagonist-II) levels were elevated. Contrast-enhanced computed tomography revealed perinodular enhancement in the arterial and portal phases. Another tumor was detected in liver segment 2, which was homogeneously enhanced in the arterial phase, followed by washout in the portal and late phases. Based on these imaging findings, we diagnosed the tumor in segment 3 as a solitary cholangiocellular carcinoma and the tumor in segment 2 as a solitary HCC. Lateral sectionectomy of the liver was performed. Microscopically, spindle-shaped and epithelioid cells were present in the tumor in segment 3. On immunohistochemistry, the tumor cells were positive for CD31 and CD34, focally positive for D2-40, and negative for AE1/AE3. Therefore, the tumor in segment 3 was ultimately diagnosed as an EHE and the tumor in segment 2 as a well-differentiated HCC. Preoperative diagnosis of EHE is difficult owing to the lack of specific findings. Intratumoral calcification, halo sign, and lollipop sign are occasionally found in EHE and are useful imaging findings for diagnosis. Clinical behavior is unpredictable, ranging from indolent growth to rapid progression. Clinical or pathological predictors of the course of EHE are urgently required.