Osteoblastoma

Osteoblastoma is a benign but aggressive tumor of bone (it can attain a large size and is not self-limiting). It is a rare bone ­forming tumor that represents less than 1% of all bone tumors. Mostly occurs in 10 to 30 years old patient, where male > female (3:1).

40% to 50% of the lesions are located in the posterior elements of the spine. Other locations include proximal humerus, and hip.

See Also: Osteosarcoma

Clinical Evaluation

The most common symptom is pain that may be similar to that produced by an osteoid osteoma (worse at night and relieved by nonsteroidal anti inflammatory drugs).

In the spine, painful scoliosis or neurological deficit may be present.

In the lumbar spine, signs and symptoms of nerve root compression may be evident, whereas in the thoracic spine, spinal cord compression is more common.

The tumor usually is slow growing, and symptoms may be present for 1 to 2 years before a diagnosis is made.

Imaging Evaluation

Anterior-posterior AP and lateral views of the affected area is recommended.

Radiology findings include:

• The classic appearance of a mineralized central nidus (> 2cm) with a surrounding radiolucent halo and reactive sclerosis.
• The lesion may be purely radiolucent, sclerotic, or mixed.
• Lesions may be diaphyseal or metaphyseal, and they may be primarily cortical or intramedullary.
• Extension into the soft tissue is rare except in the spine, where soft tissue extension is common.

CT scan is necessary to fully evaluate lesion.

Bone scan reveals hot with intense focal uptake.

Histology

The lesion is look like an osteoid osteoma. Fibrovascular stroma appearance with production of osteoid and primitive woven bone.

Bony trabeculae are lined by a single layer of osteoblasts (may be important in differentiating osteoblastoma from osteosarcoma). There is a sharp circumscription and a loose arrangement of the tissue.

Features favoring a malignant diagnosis include permeation of surrounding tissue and sheets of osteoblasts without bone production.

Differential Diagnosis

Osteoblastoma differential diagnosis include:

1. Osteosarcoma.
2. Aneurysmal Bone Cyst.
3. Osteomyelitis.
4. Osteoid osteoma.

See Also: Differential Diagnosis for Bone Lesions

Differentiation between osteoblastoma and aggressive osteoblastoma

See Also: Differential Diagnosis for Bone Lesions

Osteoblastoma Treatment

In the literature, the role of radiation therapy in the management of osteoblastoma is controversial, and open surgery remains the mainstay treatment for this lesion.

Osteoblastoma treatment consists of extended curettage or resection with bone grafting of the defect may be necessary.

Osteoblastoma spine treatment, instrumented fusion may be necessary if resection causes instability. Some authors recommend adjuvant radiation therapy for spinal lesions because revision surgery for recurrences in this area is difficult.

As follow ­up care, patients should have serial radiographs of the primary site and of the chest.

References & More

1. Campbel’s Operative Orthopaedics 12th edition Book.
2. Millers Review of Orthopaedics -7th Edition Book.
3. Limaiem F, Byerly DW, Mabrouk A, Singh R. Osteoblastoma. 2022 Nov 15. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan–. PMID: 30725639.
4. Limaiem F, Byerly DW, Mabrouk A, et al. Osteoblastoma. [Updated 2022 Nov 15]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK536954/
5. Wu M, Xu K, Xie Y, Yan F, Deng Z, Lei J, Cai L. Diagnostic and Management Options of Osteoblastoma in the Spine. Med Sci Monit. 2019 Feb 20;25:1362-1372. doi: 10.12659/MSM.913666. PMID: 30785872; PMCID: PMC6391855.
6. Nemoto O, Moser Jr, Rp, Van Dam BE, et al. Osteoblastoma of the spine. A review of 75 cases. Spine. 1990;15(12):1272–80.