CT features of hepatic metastases from hepatoid adenocarcinoma Min-Yung Chang, 1,2,3 Hye Jin Kim, 1,2,4 Seung Hyun Park, 1,2 Hyunki Kim, 5 Dong Kyu Choi, 6 Joon Seok Lim, 1,2 Mi-Suk Park, 1,2 Myeong-Jin Kim, 1,2 Honsoul Kim 1,2 1 Department of Radiology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea 2 Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Republic of Korea 3 Present address: Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea 4 Present address: Department of Radiology, Ajou University School of Medicine, Suwon, Republic of Korea 5 Department of Pathology, Yonsei University College of Medicine, Seoul, Republic of Korea 6 New Drug Development Center, Daegu-Gyeongbuk, Medical Innovation Foundation (DGMIF), Daegu, Republic of Korea Abstract Purpose: The purpose of this study was to report the imaging presentation of hepatic metastases from hepa- toid adenocarcinoma (HAC). Methods: We retrospectively identified 11 patients (10 men and 1 woman; median age 66) with HAC liver metastasis who underwent contrast-enhanced computed tomography (CT) which included arterial phase and portal venous phase. Two radiologists analyzed the imaging parameters, which included the enhancement pattern on arterial and portal phase images, necrosis, venous thrombi, and overall imaging diagnosis, and arrived at a consensus. Results: On arterial phase, the liver lesions had global hyper-enhancement (n = 0), heterogeneous hyper-en- hancement (63.6%; n = 7/11), peripheral hyper-en- hancement (n = 0), iso-enhancement (n= 0/11), or hypo-enhancement (36.4%; n= 4/11). On portal venous phase, homogenous hypo-enhancement (18.2%; n= 2/ 11) and heterogenous hypo-enhancement (81.8%; n= 9/ 11) were observed. Venous thromboses occurred in four patients (36.4%; n= 4/11). The overall imaging diag- noses were ‘‘HCC-like’’ in seven patients (63.6%; n= 7/ 11), ‘‘indeterminable’’ in 1 patient (9.1%; n= 1/11), and ‘‘HCC-unlike’’ in three patients (27.3%; n= 3/11). Conclusions: The imaging features of HAC liver metas- tasis were varied. Arterial phase enhancement coupled with venous phase washout (resembling HCC imaging features) was a major finding, but arterial phase hypo- enhancement (distinct from HCC imaging features) was also frequently encountered. Key words: Hepatoid adenocarcinoma—CT—Liver metastasis—Hepatocellular carcinoma Hepatoid adenocarcinoma (HAC) is a rare subtype of extra-hepatic adenocarcinoma that histopathologically resembles hepatocellular carcinoma (HCC). HAC is characterized by a ‘‘hepatoid’’ histologic morphology and an excessive production of alpha-fetoprotein (AFP). HAC develops most frequently in the stomach, but can involve various organs, including but not limited to, the gall- bladder, lung, esophagus, pancreas, colon, and rectum [1– 4]. The clinical course of this disease entity is extremely aggressive and survival is poor, primarily owing to extensive hematogenous liver metastasis and early nodal metastasis [5–9]. Precise diagnosis of HAC liver metastasis often becomes challenging, even when a liver biopsy is performed, and can be indistinguishable from HCC [2, 10]. This difficulty with diagnosis is exacerbated when li- ver metastasis is the first clinical manifestation of the disease and/or tissue of the liver lesion is not retrievable for microscopic examination. Under such circumstances, establishing a reasonable therapeutic strategy will greatly depend on the radiological diagnosis. Literature describing the radiological findings of HAC liver metastasis is sparse, reflecting the rarity of this disease entity. A recent article regarding computed tomography (CT) findings of eight patients (of whom 6 underwent a dynamic CT scan) is the largest study regarding HAC liver metastasis imaging, to our knowl- edge [11]. A few case reports are also available [12–16]. These studies consistently report that the imaging fea- Correspondence to: Honsoul Kim; email: pine0205@yuhs.ac ª Springer Science+Business Media New York 2017 Abdominal Radiology Abdom Radiol (2017) DOI: 10.1007/s00261-017-1150-3