ObjectiveTo explore the clinical, imaging, and pathological features of patients with synchronous double primary hepatocellular carcinoma and intrahepatic cholangiocarcinoma (sdpHCC-ICC), to enhance our understanding of the disease and reduce the rate of misdiagnosis and missed diagnosis.MethodsThe clinical, imaging, and pathological data of patients who were histologically confirmed as sdpHCC-ICC in West China Hospital of Sichuan University between January 1st 2014 and December 31st 2018 were studied retrospectively.ResultsA total of 11 patients with sdpHCC-ICC were screened for the study, of which 10 were male and 1 was female. The median age of patients was 55.6 years (ranged from 47 to 73 years). Eight patients were chronically infected with hepatitis B virus. Both increased alpha-fetoprotein and carbohydrate antigen 19-9 were observed in 8 patients. Contrast enhanced CT was performed in 8 cases, color doppler ultrasound in 4 cases, enhanced MRI in 3 cases, and contrast-enhanced ultrasound in 1 case. Among them, one solitary lesion was found in 2 patients, and two or more lesions were observed in 9 patients. Most of the patients had typical imaging performance of hepatocellular carcinoma (HCC): 8 patients showed strong enhancement of HCC during the hepatic arterial phase and progressive hyper-attenuation on venous and delayed phases, 1 patient showed peripheral rim enhancement in the arterial phase of intrahepatic cholangiocarcinoma (ICC) in another lesion could be observed at the same time. None of the 11 patients with sdpHCC-ICC was diagnosed accurately before operation. All patients underwent surgical treatment. HCC lesions were distributed in all parts of the liver, while ICC lesions were located in the right lobe of the liver in 10 cases. The median diameter of HCC and ICC was 3.5 cm and 2.1 cm, respectively. All of them were confirmed by hematoxylin-eosin staining and immunohistochemistry.ConclusionsThe clinical characteristics of sdpHCC-ICC are usually atypical. It is difficult to make an accurate preoperative diagnosis. Tumor markers may be valuable to the diagnosis of sdpHCC-ICC. The definite diagnosis of sdpHCC-ICC depends on pathological examination.