High fluorodeoxyglucose ((18)F)PET-uptake lymph nodes in a patient with chordoma: Tumor metastasis or sarcoidosis?

Male, 48 FINAL DIAGNOSIS: Chordoma Symptoms: - - Clinical Procedure: - Specialty: Neurology. Challenging differential diagnosis. Fluorodeoxyglucose positron emission tomography (FDG-PET) has been used in imaging and staging of malignancies including sacral chordomas. The author's report describes the coincident pathological diagnosis of sarcoidosis in a 48-year-old male patient with a recurrent sacral chordoma. Chordoma is a low grade malignancy with frequent systemic metastases in advanced disease. Both metastases and sarcoidosis may be high FDG uptake. Unexpected PET findings need to be biopsied in order to make appropriate clinical decision in the management of chordoma. Lymph nodes involvement in sarcoidosis and neoplastic disease can have similar FDG-PET manifestations.