Hepatocellular carcinoma-cholangiocarcinoma collision tumor with excellent therapeutic response: a case report and literature review

This article reports a rare case of a collision tumor composed of intrahepatic cholangiocarcinoma (ICC) and hepatocellular carcinoma (HCC). The patient is a 54-year-old male with hepatitis B virus-related cirrhosis and three focal lesions located in liver segments S8, S7, and S4. Contrast-enhanced computed tomography (CT) revealed the following imaging features: the S8 lesion demonstrated marked arterial phase enhancement, consistent with typical HCC; the S7 lesion exhibited rim-like arterial enhancement, characteristic of ICC; and the S4 lesion showed peripheral nodular enhancement in the arterial phase, indicative of a hemangioma. Laboratory findings showed a mildly elevated alpha-fetoprotein level (15.39 IU/mL)and significantly abnormal transaminase levels. Due to the patient's overall condition being unsuitable for surgical resection, an ultrasound-guided biopsy was performed after excluding extrahepatic metastases. Histopathological examination confirmed that the S7 nodule was moderately differentiated cholangiocarcinoma, while the S8 nodule was hepatocellular carcinoma. Following diagnosis, the patient underwent interventional therapy, immunotherapy, and chemotherapy. At the 9-month follow-up after diagnosis, the patient was in good general condition with no significant abnormalities in liver and kidney function, complete blood count, or other routine tests. Follow-up contrast-enhanced abdominal CT demonstrated a reduction in tumor diameter from 6.7 cm to 2.8 cm in segment S7, representing approximately 60% decrease in tumor burden and from 3.5 cm to 1.0 cm in segment S8, corresponding to roughly 72% decrease in tumor burden. This disease entity is extremely rare. To date, it has been definitively reported in the literature only by Hong, Chang Kyun, et al. in 2007 and Al Hamoudi, Waleed, et al. in 2012. By analyzing the clinical, imaging, and pathological characteristics of this case and reviewing the relevant literature, we aim to offers a valuable clinical reference for the formulation of comprehensive treatment regimens for unresectable HCC-ICC collision tumors.