Pulmonary pleomorphic carcinoma producing granulocyte–macrophage colony-stimulating factor: report of a case

We report a case of lung cancer producing granulocyte–macrophage colony-stimulating factor (GM-CSF). The patient, a 55-year-old woman, was found to have leukocytosis (leukocytes 28.8 × 10 3 /mm 3 ) with eosinophilia (eosinophils 24.5%) without any evidence of infection or allergy. The serum concentration of GM-CSF was elevated to 44 pg/ml (normal range <2.0 pg/ml), which might have induced the leukocytosis and eosinophilia. We performed left pneumonectomy and diagnosed a pleomorphic carcinoma with p-T2bN0M0, based on histological examination of the resected tumor. Immunohistochemical examination revealed GM-CSF. The serum level of GM-CSF decreased to within the normal range 8 days after surgery. At the time of writing, 16 months after the surgery, she was alive without disease. To our knowledge, this represents the first case report of a GM-CSF-producing tumor effectively treated by surgical resection.