The characteristics of FDG PET/CT imaging in pulmonary Langerhans cell sarcoma.

A 53-year-old man, who was a heavy smoker, presented with recent severe cough. Radiography demonstrated a large pulmonary mass in the right upper lung. FDG PET/CT demonstrated heterogeneous high-grade activity in the pulmonary mass located in the right upper lung (standardized uptake value of 20), with central necrosis, bilateral upper mediastinal lymphadenopathy, right supraclavicular lymphadenopathy, direct left sternal manubrium invasion, and distal bilateral peripheral lung metastasis. Histology revealed significant malignant cytologic features and CD1a- and S-100-positive cells by immunohistochemistry staining, typical for Langerhans cell sarcoma.