Liver metastasis from neuroendocrine carcinoma after the use of the new direct-action antivirals against hepatitis C virus in a patient with past history of hepatocellular carcinoma.

The use of the new direct-action antivirals against hepatitis C virus provides very high viral eradication rates. However, various recently published articles recommend caution with their use after the appearance of some cases of de novo tumors (originated in hepatic and extra-hepatic locations) and a possible shorter time period of recurrence of hepatocellular carcinomas previously treated with surgery or loco-regional therapies. The sudden drop of the number of natural killer cells secondary to the use of these new medicines has been suggested as one of the possible mechanisms responsible for this process. However, due to the controversy concerning this subject and the absence of long-term follow-up studies in clinical practice, caution is needed before definitive conclusions are settled. We present the case report of a patient diagnosed of chronic liver disease secondary to hepatitis C virus infection and a past history of hepatocellular carcinoma in complete remission after radiofrequency ablation. He was treated with the new direct-action antivirals reaching sustained viral response. Six months later, the patient was diagnosed with liver metastasis from a small-cell neuroendocrine tumor of unknown primary site.