Age / Sex : 22 / M

Chief complaint :

Back pain

What is your impression?

Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer).

Courtesy : Sun-Young Park, Hallym University Sacred Heart Hospital  

Discussion

Answer:  

Spinal osteoid osteoma

Findings:

MRI: On T1- and T2WI, a small round shaped lesion at right superior articular process of L1 surrounded by bone marrow edema. Bone marrow edema is noted at right pericle, lamina, transverse process and superior articular process of L1 with adjacent soft tissue signal change.

CT: nidus with reactive sclerosis at right pedicle and superior articular processs of L1

Discussion:

 Spinal osteiod osteoma usually affect the posterior elements. In the spine, the lumbar spine followed by the cervical and then the dorsal spine are most commonly affected. The patients are usually young and present with back pain. The classical clinical presentation of spinal osteoid osteoma is that of painful scoliosis. Other clinical features include nerve root irritation and night pain. Pain relief with aspirin is classical. However, the typical symptoms of osteoid osteoma are reported to occur only in one half to two thirds of patients. On MRI, an area of edema in the posterior and lateral aspect of a vertebral body with pedicle involvement is classically seen. The presence of extensive perinidal edema in osteoid osteoma is thought be due to high levels of cyclo-oxygenase–2 expression in neoplastic osteoblasts in the nidus. Gadolinium administration has been suggested to improve conspicuity and detection of the nidus. A CT is needed after the MRI to clearly identify the nidus with surrounding lucency. The sclerotic reaction can also be well assessed. Bone scintigraphy has been advocated to localise the vertebral level in young patients with clinically suspected osteoid osteoma. Bone scintigraphy is almost invariably positive.

Differential diagnosis

Stress fracture

Intracortical abscess

References:

Harish S, Saifuddin A. Imaging features of spinal osteoid osteoma with emphasis on MRI findings. Eur Radiol. 2005;15 (12): 2396-403. 

Chai JW, Hong SH, Choi JY et-al. Radiologic diagnosis of osteoid osteoma: from simple to challenging findings. Radiographics. 2010;30 (3): 737-49.