A Case of Lung Histiocytic Sarcoma That Produced Granulocyte Colony-stimulating Factor

Abstract

━━ Background. Histiocytic sarcoma (HS) is extremely rare, and few studies have reported paraneoplastic syndromes with HS. We encountered a case of lung HS expressing granulocyte colony-stimulating factor (G-CSF). Case. A 50-year-old woman who presented with fatigue was referred to our hospital for a further examination of leukocytosis. Chest computed tomography (CT) revealed a 28×22×43-mm nodule in the left upper lung, and positron emission tomography (PET)/CT showed an abnormally high uptake of fluorodeoxyglucose (FDG) in the nodule. The level of serum G-CSF was abnormally high (183.2 pg/ml), so we suspected a G-CSF-producing tumor of the lung and performed left upper lobectomy with mediastinal lymph node dissection for the diagnosis and treatment. An immunohistochemical evaluation indicated HS of the lung, and the tumor cells were partly positive for anti-human G-CSF antibody. The final pathological diagnosis was lung HS expressing G-CSF. Postoperatively, the patient has remained relapse-free for 12 months without adjuvant chemotherapy. Conclusion. We experienced an extremely rare case of lung HS with the expression of G-CSF. Currently, the patient is still alive with no recurrence, although further close follow-up is essential.