Background: Hepatocellular carcinoma (HCC) can occasionally develop with other non-HCC cell types, either in a combined type or collision type. A collision tumor is defined as two histopathologically distinct tumors of the same organ lacking a clear transition zone. Hepatic collision tumors are rare. Among them, "hepatocellular carcinoma-hepatic neuroendocrine carcinoma" (HCC-NEC) collision tumors are especially rare and information about them is rarely published.
Case summary: A 48-year-old man with typical findings of HCC underwent consecutive therapies, including radiofrequency ablation and embolization prior to resection. Diagnosis of the HCC-NEC collision tumor in the right liver and another HCC in the left liver was established following surgical resection. The patient displayed NEC metastasis following resection and succumbed to septicemia after 2 more rounds of chemotherapy. To our knowledge, this is the 25th reported case of mixed HCC-NEC tumor. The rarity of HCC-NEC collision tumors and the absence of diagnostic criteria make it difficult to differentiate this condition from simple liver tumors, especially in patients with chronic liver disease.
Conclusion: Our case highlights the difficulty in accurately diagnosing HCC-NEC in the absence of histological evidence. The prognosis is poor for this condition, although ultrasound-guided liver biopsy can be helpful to establish a prompt diagnosis. Further accumulation of such cases could help establish an accurate diagnosis earlier. Early discovery of NEC may allow for better treatment strategies and better prognoses.
Keywords: Case report; Collision tumor; Combined tumor; Hepatocellular carcinoma; Neuroendocrine tumor.
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