Age / Sex : 7 / F

Age / Sex : 7/female

Chief complaint : back pain

Osteoid osteoma

Discussion

Findings:

1)     Radiograph: Thoracic scoliosis

2)     Bone scan: A focal increased uptake at T5 right side.

3)     MRI: Mild expansible bone lesion with mild enhancement, and edema in the surrounding bone marrow and soft tissue involving right pedicle and transverse process of T5.

4)     CT: Nidus containing small central area of calcification in the right pedicle and transverse process of T5.

Differential Diagnosis:

 Osteoid osteoma, Abscess, Osteoblastoma

Diagnosis:  

Osteoid osteoma in the spine

Discussion:

 Osteoid osteoma of the spine constitutes 10% of all osteoid osteomas. Patients are affected between the ages of 10 and 20 years, while men are affected two to three times more frequently than women. Most spinal osteoid osteomas arise from the posterior osseous elements. The lumbar vertebrae are typically affected. Painful scoliosis, focal or radicular pain, gait disturbance,

and paraspinal muscle atrophy are among the clinical manifestations of disease. Osteoid osteoma characteristically is localized to the concave portion near the apex of the scoliotic curve. The pain is often worse at night and usually can be ameliorated with salicylates. On radiographs, the tumor appears as an osteolytic area less than 2 cm in diameter (representing the nidus) that is surrounded by sclerosis. Central calcification may be present. Surrounding sclerosis, soft tissue edema, or bone marrow edema may obscure the nidus. Bone scintigraphy shows significant increased radionuclide uptake by the nidus. CT is particularly useful for detecting the nidus, which appears as a low attenuation focus surrounded by sclerosis. On MR images, osteoid osteoma shows low-to-intermediate signal intensity on T1-weighted images and intermediate-to-high signal intensity on T2-weighted images. MR imaging may also show an associated soft tissue mass. Both the nidus and the mass enhance after the intravenous administration of contrast material.

References:

1.     Daphne J. Theodoroua, Stavroula J. Theodoroua, David J. Sartoris. An imaging overview of primary tumors of the spine: part 1. Benign tumors. Clinical Imaging 2008; 32:196-203