Orthopedic Oncology cases osteoid osteoma 3

A 23-year-old male presents to your office complaining of progressive low back pain for the past 6 months. The pain is at its worst at night. He, in addition, notes that he has been taking ibuprofen, because this medication works well to relieve his pain.

 

He denies history of trauma or history of back pain before this year. He has no radicular symptoms. Physical examination reveals negative straight-leg raise, and he has full flexion and extension of the lumbar spine without increase in pain. X-rays taken in the office are negative.

 

What is the next step in evaluation and management of this patient?

Obtain oblique x-rays to reveal pars defect

 

Prescription for physical therapy

 

Electromyography and nerve conduction velocity studies

 

Thin-cut CT scan of the lumbar spine

 

 

 

Discussion

The correct answer is (D). The patient’s history is most consistent with an osteoid osteoma, which is a benign osteoblastic bone tumor that involves a radiolucent nidus surrounded by a ring of sclerotic bone, and can occur in the vertebral arch. Nocturnal pain is a classic finding, as is good relief with NSAIDs since high prostaglandin and cyclooxygenase levels within the lesion are thought to play a role in pain generation. They are usually <1 cm in diameter and frequently missed on plain radiographs, therefore thin-cut CT scan is often the key to diagnosis because it will identify the radiolucent nidus. A pars defect is less likely, since he has no pain with flexion and extension. Physical therapy is not appropriate without a diagnosis at this time, and it is unlikely that EMG/NCV testing will be helpful since he has no neurologic symptoms.

 

Which of the following is true regarding the natural history of osteoid osteoma?

Benign lesion with rare lung metastases

 

Self-limiting which generally resolves in 2 to 4 years

 

Rarely require treatment when found in long bones, but aggressive treatment when present in vertebrae is always recommended

 

Benign lesion, with recurrence rate of 30% to 50% after treatment

 

 

 

Discussion

The correct answer is (B). Unlike osteoblastomas, the growth characteristics of osteoid osteoma are self-limited. Pain may be an indication for treatment, but if given time these lesions will resolve with no malignant potential (average 3 years). Recurrence rates after radiofrequency ablation are <10%.

 

Which of the following is true regarding an osteoid osteoma causing a painful scoliosis?

The lesion is found at the center of the concavity of the curve, and removal of the lesion will usually allow resolution of the curve without further treatment

 

The lesion is found at the center of the concavity of the curve, and correction of the curve will require posterior spinal fusion

 

The lesion is found at the apex of the convexity of the curve, and removal of the lesion will usually allow resolution of the curve without further treatment

 

The lesion is found at the apex of the convexity of the curve, and correction of the curve will require posterior spinal fusion

 

Discussion

The correct answer is (A). When causing a painful scoliosis, an osteoid osteoma is usually at the center of the concavity of the curve. Depending on the age of the child and the duration of spinal asymmetry, treatment of the osteoid osteoma will generally lead to resolution of the curve without need for further surgical correction.

 

All are acceptable treatments for osteoid osteoma except:

Percutaneous radiofrequency ablation with CT-guided probe

 

Surgical resection

 

Long-term medical management with NSAIDs or aspirin

 

Intralesional injection of methylprednisolone acetate

 

 

 

Discussion

The correct answer is (D). The standard of care for osteoid osteoma is percutaneous radiofrequency ablation (RFA) of the lesion, where a CT-guided probe is inserted into the lesion and heated to 90°C for 4 to 6 minutes. This produces a 1-cm area of necrosis. Surgical resection or curettage is also acceptable treatment when the lesion is close to the spinal cord or nerve roots, other sensitive areas, or if RFA is not available. Patients who opt for nonsurgical management can control symptoms with long-term NSAIDs or aspirin, and usually after an average of 3 years these lesions cease to be painful as they have self-limited growth.

 

 

 

Objectives: Did you learn...?

 

Clinical and imaging features of osteoid osteoma?

 

To differentiate osteoid osteoma and osteoblastoma? Treatment of osteoid osteoma?