Extraskeletal osteosarcoma (EO) is a rare malignancy and its FDG PET/CT imaging is seldom reported. We present staging and restaging images of a FDG PET/CT imaging in an EO originating from paraspinous musculature. Initial staging FDG PET/CT scan showed increased metabolism of a mass in the right paraspinous region without nodal or distant metastasis. The patient underwent tumor resection and radiation therapy with a pathological diagnosis of EO. Restaging FDG PET/CT imaging demonstrated postsurgical changes without nodal or distant metastasis. This case demonstrates the clinical relevance of FDG PET/CT imaging for staging and restaging EO.