Breast osteoblastoma and recurrence after resection: Demonstration by color Doppler ultrasound.

Osteoblastoma is a rare benign primary bone tumor, which occurs in any part of the skeleton. Extraskeletal osteoblastoma is rather rare. We presented an extremely rare case of extraskeletal osteoblastoma located in the breast. The tumor recurred 7 months later after resection and transformed to aggressive osteoblastoma. The histopathological features, ultrasonic manifestations and ultrasonic differential diagnoses of the primary and recurrent tumors were discussed. The recommended treatment of the tumor is surgical excision. Due to its tendency of recurrence and potential malignant transformation, adequate resection and careful follow up is essential.