coincidental occurrence of hepatocellular carcinoma and cholangiocarcinoma (collision tumors) after liver transplantation: a case report

coincidental occurrence of hepatocellular carcinoma (hcc) and cholangiocarcinoma, known as “collision tumors”, within a cirrhotic liver is rare. herein, we report a case of liver transplantation (lt) in a patient with such collision tumors. our patient was a 56-year-old woman with hepatitis c virus-related cirrhosis and 2 focal hepatic lesions, measuring 1.5 and 3 cm, in the liver segments 8 and 5, respectively. the lesion on segment 8 showed the typical radiological characteristics of hcc; however, the lesion in segment 5 showed an atypical vascular pattern and was closely associated with the inferior vena cava. serum alpha-fetoprotein level was normal and serum carbohydrate antigen 19-9 (ca19-9) level was slightly elevated (63 u/ml); the extrahepatic spread of hcc was ruled out. the patient underwent an uneventful deceased-donor lt. histopathological examination of the explant confirmed that the lesion on segment 8 was an hcc, but surprisingly, the lesion on segment 5 was found to be a cholangiocarcinoma. six months after lt, the serum ca19-9 level was markedly elevated (255 u/ml), and the patient began experiencing abdominal pain. magnetic resonance imaging showed enlarged hilar and paraaortic lymph nodes that were suggestive of metastases; histopathological analysis using ultrasound (us)-guided biopsy confirmed recurrent cholangiocarcinoma. unfortunately, the patient died because of tumor recurrence 9 months after lt.rncollision tumor resulting from the co-existence hcc and cholangiocarcinoma in a cirrhotic liver is rare and has a negative impact on the outcome of lt. atypical vascular pattern and elevated serum ca19-9 levels are suggestive of such tumors; patients with these findings should undergo a targeted biopsy to rule out the coincidental occurrence of hcc and cholangiocarcinoma.