Osteoblastoma - Foot and Ankle

Summary
Description

Osteoblastoma is an osteoid producing benign bone lesion which can demonstrate
aggressive clinical behavior.

People and Age
The mean age of the patient is about 22 years.
Brief description of the xray
On x-ray, osteoblastomas appear as a radio-lucent defect with a central density due to ossification.
Brief desc of tx
Surgical resection by curettage, intralesional excision or en-bloc excision are all treatment options depending on the site. Cryosurgery, radiation and chemotherapy may have a role in aggressive and surgically unresectable lesions of the spine.
Benign or Malignant
Body region
Most Common Bones
Periosteal reaction
Tumor behavior
Tumor density
Complete Information on this Tumor
Introduction and Definition

Osteoblastoma is an osteoid producing benign bone lesion which can demonstrate
aggressive clinical behavior. The foot is the 3rd most common location of osteoblastoma after the spine and the femur. 12.5% of osteoblastoma occur in the bones of the foot. Most occur in the hind foot, and the talus is most commonly affected bone. In one review of 41 osteoblastomas in the foot, two evolved into malignant sarcomas.

Incidence and Demographics
The mean age of the patient is about 22 years.
X-Ray Appearance and Advanced Imaging Findings
On x-ray, osteoblastomas appear as a radio-lucent defect with a central density due to ossification. The lesion is well circumscribed and may have a surrounding sclerosis. The tumor demonstrates increased isotope
uptake on bone scan.
Differential Diagnosis
Careful correlation of the clinical, radiological, and histological information is required in order to determine the correct treatment. There is a lack of consensus as to what histological characteristics are associated with more or less aggressive behavior. (temple, izel, FAI 1998:698)
Preferred Biopsy Technique for this Tumor
A biopsy is usually performed to confirm the diagnosis.
Histopathology findings
On gross examination, osteoblastomas are red to tan in color with hemorrhagic areas. The compact tissue is granular, friable and gritty.

The classic microscopic finding of osteoblastoma is irregular spicules of mineralized bone and eosinophilic osteoid rimmed by osteoblasts. The vascular stroma is characterized by pleomorphic spindle cells. The tumor cells differentiate into osteoblasts which make varying amounts of osteoid and woven bone. Cartilage production is a very rare finding in an osteoblastoma and should raise the suspicion of osteosarcoma.
Treatment Options for this Tumor
Surgical resection by curettage, intralesional excision or en-bloc excision are all treatment options depending on the site. Cryosurgery, radiation and chemotherapy may have a role in aggressive and surgically unresectable lesions of the spine.