OSTEOID OSTEOMA OF THE PATELLA PRESENTING AS CHRONIC ANTERIOR KNEE PAIN Case report and review of the literature

Osteoid osteoma is a benign bone forming tumor with a characteristic radiographic appearance. femur and tibia is the frequent site of involvement. osteoid osteoma in the patella is a rare condition of which only a few cases have been reported in the literature. non-specific knee pain, difficulty to distinguish nidus, and lack of typical sclerotic bone formation in plain radiographs cause a delay in diagnosis. we report a 15 years old girl with anterior left knee pain since 1.5 year. imaging findings and biopsy of the lesion confirmed osteoid osteoma. the pain was relived after surgical resection of the tumor and patient was symptom free with no evidence of recurrence at 12 months after surgery.