[A case of large cell carcinoma of the lung which is suspected of producing granulocyte colony-stimulating factor].

A 41-year-old male complaining of fever and left shoulder pain was admitted to our hospital for further examination of an abnormal shadow on chest X-ray film. His laboratory data on admission showed marked leukocytosis and elevation of serum alkaline phosphatase. The diagnosis of large cell carcinoma of the lung was made by percutaneous biopsy and he was staged clinically as T3N0M0. Chemotherapy including CDDP and VDS resulted in resolution of symptoms and normal laboratory data. After three courses of chemotherapy, he underwent left upper lobectomy with chest wall resection. Pathological diagnosis of the resected tumor was large cell carcinoma with giant cells, and he was staged postoperatively as T3N0M0. Since colony stimulating activity was demonstrated in both homogenate of tumor cells and tumor conditioned medium, and preoperative serum granulocyte colony-stimulating factor (G-CSF) was 105 pg/ml, we concluded that leukocytosis in this patient was caused by G-CSF produced by tumor cells. The patient was in good health two years after surgery with no signs of recurrence.