A 51-year-old man presented with recurrent gliosarcoma and increasing cough over the last months. On F-FDG PET/CT, solid lung masses with high F-FDG uptake were present. A biopsy taken from a lung lesion indicated distant metastases from gliosarcoma. Gliosarcoma, a rare malignant central nervous system tumor, presents with extracranial metastases in only less than 10%. As highlighted by this case, F-FDG PET/CT can be used for whole-body staging in patients with metastatic brain tumor. Vice versa, highly F-FDG-avid lung lesions in patients with brain tumors should lead to distant metastases as differential diagnosis despite their rare occurrence.
