Combined hepatocellular carcinoma and neuroendocrine carcinoma with sarcomatous change of the liver after transarterial chemoembolization

Primary hepatic neuroendocrine carcinoma is rare and its origin is not clearly understood. An admixture of hepatocellular carcinoma (HCC) and neuroendocrine carcinoma is particularly rare. Here, we report a patient with an extremely rare combination of HCC and neuroendocrine carcinoma of the liver. To our knowledge, this is the first reported case in which the carcinoma showed sarcomatous change. The patient was a 76-year-old man who had received outpatient treatment for chronic hepatitis C. On abdominal computed tomography (CT), the hepatic tumor was enhanced in the arterial phase but its density was lower than that of normal liver in the portal phases. His serum α-fetoprotein (AFP) level was very high. Therefore, transarterial chemoembolization (TACE) was performed based on the diagnosis of HCC. Ten months after TACE, his serum AFP level had increased to the level measured before TACE. Partial hepatectomy was performed because CT revealed poor enhancement of the recurrent tumor. Histopathologically, the tumor consisted of two distinct components: moderately differentiated HCC was intermingled with a neuroendocrine carcinoma, which was accompanied by sarcomatous changes. Immunohistochemically, the neuroendocrine carcinoma cells were positive for CD56, chromogranin A and neuron-specific enolase, and negative for AFP. The sarcomatous area was positive for AE1/3 and CD56, consistent with sarcomatous change of neuroendocrine carcinoma. The neuroendocrine carcinoma and/or sarcomatous change may have been due to phenotypic changes and/or dedifferentiation of HCC induced by TACE. Six months after surgery, the patient was diagnosed with metastasis of the neuroendocrine carcinoma to sacral bone. He died 7 months after surgery.