Vertebral osteoid osteoma masquerading as a malignant bone or soft-tissue tumor on MRI.

Purpose: Four pediatric patients were sent to our institution with the diagnosis of soft-tissue/malignant bone tumor. In all cases an MRI was the initial study performed for neck or back pain. All were surgically proven to have an osteoid osteoma/osteoblastoma (OO) as a final diagnosis. The MRI findings are reviewed.

Methods: Four patients, three boys and one girl, ranging in age from 5 to 17 years, presented with symptoms of neck or back pain for 2 months to 2 years. Two had neurological findings. All patients underwent MRI.

Results: All MRIs demonstrated decreased T1 signal and increased T2 signal in the soft tissues and bone surrounding the lesions consistent with edema. Enhancement was observed in the adjacent soft tissues and in the lesion nidus retrospectively.

Conclusion: Investigating neck or back pain with an initial MRI may lead to misleading diagnoses unless the radiologist is aware of the typical MRI appearance of vertebral osteoid osteoma.