Granulocyte colony-stimulating factor-producing squamous cell carcinoma of the tongue exhibiting characteristic fluorine-18 deoxyglucose accumulation on positron emission tomography-computed tomography: A case report

BACKGROUND Granulocyte colony-stimulating factor (G-CSF) is a cytokine produced in inflammatory environments that induces differentiation and proliferation of neutrophils in bone marrow. We report a rare case of aggressive G-CSF-producing squamous cell carcinoma of the tongue exhibiting fluorine-18 deoxyglucose (FDG) accumulation in primary lesion, metastatic lymph nodes, spleen, and bone marrow on positron emission tomography-computed tomography (PET/CT). CASE SUMMARY We report a 58-year-old female with a rapid enlarged lingual mass with partial necrosis. Blood test results from the initial examination revealed a leukocyte count of 21380/mu L. On PET/CT, extensive FDG accumulation was observed in the tongue and bilateral cervical lymph nodes, with elevated FDG accumulation in the spleen and bone marrow although no distant metastases were observed. We performed partial glossectomy and bilateral neck dissection. Immunohistochemical staining with G-CSF antibodies on biopsy specimen and resected samples revealed that both specimens were G-CSF positive. This is a rare case of G-CSF producing tongue carcinoma with elevated FDG accumulation in the spleen and bone marrow. CONCLUSION In patients with the tongue cancer and hyperleukocytosis, where FDG accumulations in the spleen and bone marrow are observed using PET/CT and when these accumulations are not caused by metastasis, G-CSF-producing tumors, with associated poor prognosis, should be considered.