Intra articular osteoid osteoma presenting as ankle synovitis

A 16 year old male patient presented to our hospital with chronic swelling and pain of left ankle and gradually increasing restriction of movement. The patient had been worked up elsewhere and X-rays along with blood work and arthrocentesis had been performed. The
patient was managed conservatively with rest and anti- inflammatory medication but was not relieved completely. At our hospital we performed repeat X-rays and MRI of the affected part. The radiological investigations revealed a circumscribed lesion in the distal epiphysis of tibia with a classic nidus. A preliminary diagnosis of osteoid osteoma was made. Although about 13% of osteoid osteomas are intra-articular, the ankle per se is a rare
location for the same. The lesion was excised surgically with complete resolution of symptoms over a period of 3 months.