Abstract
The current study presents the case of a 66-year-old male presenting with fever and chest pain. Chest enhanced computed tomography scanning revealed a mass shadow in the right upper lobe with chest wall invasion. 18-Fluorodeoxyglucose-positron emission tomography (FDG-PET) identified the localized uptake of the mass lesion in the right upper lobe, in addition to diffuse uptake by the bone marrow. The laboratory data on admission revealed marked leukocytosis and an elevated C-reactive protein level (CRP). Serum concentrations of granulocyte colony-stimulating factor (G-CSF) and interleukin 6 were increased. Based on a clinical diagnosis of non-small cell lung cancer (c-T3N0M0 stage IIB), the patient underwent right upper lobectomy with chest wall resection. The histological examination showed a pulmonary pleomorphic carcinoma. Immunohistochemical analysis of the resected tumor tissues revealed positive staining for G-CSF. The patient's high-grade fever, leukocytosis, and elevated CRP level rapidly subsided following the resection. This confirmed that the tumor was a G-CSF-producing pulmonary pleomorphic carcinoma. Five months after the resection, the diffuse FDG uptake in the bone marrow was absent, even with the presence of a small pulmonary metastasis and marginal serum G-CSF elevation. Diffuse FDG uptake in bone marrow induced by G-CSF producing pleomorphic carcinoma must be taken into consideration, in order for it not to be misinterpreted as diffuse bone marrow metastases or hematologic malignancy.