G-CSF Producing Parotid Tumor; A Case Report.

We describe a rare case of granulocyte colony-stimulating factor (G-CSF) producing parotid tumor. The tumor was seen in a 59-year-old male patient. The histopathological examination revealed a poorly-differentiated adenocarcinoma. Leukocytosis was seen in the blood analysis and mature granulocytes were markedly increased in number in the peripheral blood.The patient died of focal recurrence and distant metastasis to the lung about four months after admission, even though total parotidectomy with radical neck dissection and systemic chemotherapy were attempted.This case was confirmed to be a G-CSF producing malignant parotid tumor, because high G-CSF activity was detected in the plasma, tumor secretions, pleural effusion and culture supernatant of the tumor cells.