A 26-year-old female underwent ¹⁸F-FDG PET/CT after having diagnosed as Ewing sarcoma with a biopsy from a mass lesion located at left sacroiliac region.

This finding is suggestive for malignant disease of bone invading surrounding structures.

¹⁸F-FDG PET CT demonstrated high sensitivity and specificity in pretreatment staging of Ewing sarcoma and may provide additional information that modify therapy planning. It is proposed that FDG PET could replace bone scan when the initial evaluation of the extent of disease is concerned.

A 17-year-old female who was diagnosed to have Ewing sarcoma 1 year ago is now being evaluated with 18F-FDG PET/CT for restaging, after having received chemotherapy and radiotherapy.

Multiple hypermetabolic lesions consistent with widespread metastatic disease.

¹⁸F-FDG PET CT demonstrates high diagnostic accuracy for detecting recurrence in patients with primary skeletal Ewing sarcoma with a sensitivity of 95 % and a specificity of 87 %.

A 29-year-old female who was diagnosed to have osteosarcoma at left femur underwent ¹⁸F-FDG PET/CT.

Hypermetabolic mass lesion at distal left thigh is compatible with primary malignant disease of bone. A focal increased FDG uptake located at intramedullary femur diaphysis above the primary lesion representing skip metastasis is seen. Right hilar lesion with FDG uptake is consistent with pulmonary metastasis.

Although, for osteosarcoma, FDG PET is less sensitive than bone scan for the detection of bone metastases and accuracy in detecting pulmonary metastases is lower than CT, bone and lung lesions in this case are correctly identified by PET.

A 67-year-old male status post cervical vertebral body biopsy proven to be solitary plasmacytoma underwent ¹⁸F-FDG PET/CT.

Solitary plasmocytoma involving vertebral body. Moderate FDG uptake at lesion is an expected finding for plasmocytoma.

¹⁸F-FDG PET/ CT has a high performance for initial staging of plasmacytoma (98 % sensitivity, 99 % specificity). It has the advantages of performing whole-body examinations with the ability of detecting medullary and extramedullary lesions in one single examination.

A 57-year-old male who had the diagnosis of plasmocytoma underwent ¹⁸F-FDG PET/CT for pretreatment staging.

This is consistent with extensive active multiple myeloma.

Solitary plasmocytoma may be a local manifestation of multiple myeloma and ¹⁸F-FDG PET CT may detect other unsuspected sites of bone involvement which are overlooked at other conventional imaging methods.

A 63-year-old male who was diagnosed to have multiple myeloma underwent ¹⁸F-FDG PET/CT for pretreatment staging.

This is consistent with extensive active multiple myeloma.

¹⁸F-FDG PET CT finds additional unanticipated bone lesions and upstage the patients in 33–43 % of multiple myeloma cases.

A 57-year-old female underwent ¹⁸F-FDG PET/CT for characterization of sacrococcygeal mass detected on CT.

Although the metabolic activity of the mass is subtle, the lesion is suspicious for malignancy when location and destructive nature is concerned.

The patient underwent surgery and histopathology revealed sacrococcygeal chordoma.

Chordoma is a rare malignant bone tumor derived from notochordal rests, and the most common site is the sacrococcygeal region. Chordomas are not FDG avid tumors, so chordoma should be considered when an osteolytic mass in the sacral region on FDG PET/CT is encountered, even if its metabolism is low.