[A case of thymic carcinoma producing granulocyte colony-stimulating factor]

A 73-year-old man was admitted complaining of chest pain and weight loss. A chest X-ray film and chest CT scan showed a tumorous mass in the anterior mediastinum with moderate pleural effusion. Percutaneous needle biopsy specimens from the mass resulted in a diagnosis of poorly differentiated squamous cell carcinoma of the thymus. Laboratory findings on admission showed marked leukocytosis with no evidence of infection or bone marrow metastasis. The level of serum granulocyte colony-stimulating factor (G-CSF) was abnormally high (79.2 pg/ml, normal < 30). Carcinoma cells in the specimen showed positive staining with anti G-CSF monoclonal antibody, thus indicating that they produced G-CSF. Because multiple metastatic lesions on the chest wall and liver were detected, we performed combination chemotherapy with cisplatin, vindesine and mitomycin C. After 2 courses of chemotherapy, a decrease in tumor size was verified by CT scan. As the tumor size decreased, the patients white blood cell count and serum G-CSF concentration fell to normal levels.