A case of granulocyte-colony stimulating factor-producing hepatocellular carcinoma confirmed by immunohistochemistry.

Granulocyte-colony stimulating factor (G-CSF) is a naturally occurring glycoprotein that stimulates the proliferation and maturation of precursor cells in the bone marrow into fully differentiated neutrophils. Several reports of G-CSF-producing malignant tumors have been published, but scarcely any in the hepatobiliary system, such as in hepatocellular carcinoma (HCC). Here, we encountered a 69-yr-old man with a hepatic tumor who had received right hepatic resection. He showed leukocytosis of 25,450/mL along with elevated serum G-CSF. Histological examination of surgical samples demonstrated immunohistochemical staining for G-CSF, but not for G-CSF receptor. The patient survived without recurrence for four years, but ultimately passed away with multiple bone metastases. In light of the above, clinicians may consider G-CSF-producing HCC when encountering patients with leukocytosis and a hepatic tumor. More cases are needed to clarify the clinical picture of G-CSF-producing HCC.