Chondroblastoma

About 12% of all chondroblastomas occur in the bones of the foot. Males are affected 6
times as commonly as females. The average age at presentation around 25 years,
significantly older than the average age in other parts of the skeleton.

Patients complaint of pain and swelling or a mass near the joint. The pain can be severe. The nearby joint may be locally inflamed.

Chondroblastoma in the foot most commonly occurs in subchondral areas of the talus and calcaneus as well as the calcaneal apophysis.

Radiographically, the lesion is located in the exclusively in the epiphysisis, although in the small bones of the foot the location of the epiphysis may not be obvious. The lesions appear well-defined, expansile, and lucent, and there may be stippled calcification or there may be no matrix mineralization. The tumor is adjacent to an articular surface or an apophysis. There is a lobular appearance.

CT scan is useful for defining the relationship of the tumor to the joint, the integrity of the underlying bone, and to identify intralesional calcifications.

MRI scans show the very high signal intensity on T2 weighted scans that is characteristic of cartilage lesions.

Bone scan shows avid tracer uptake in the lesion.

Chondroblastoma can behave aggressively and invade soft tissue. Benign pulmonary metastases have been observed.

Treatment of the primary lesion consists of complete curettage and bone grafting. Extending the zone of the curettage by removing two or 3 additional millimeters of bone using a mechanical bur, or by using phenol or liquid nitrogen placed in the tumor cavity have been proposed as in method to reduce the risk of local recurrence.

Recurrence is common, and recurrent lesions should be treated with repeat curettage. If a recurrent lesion is located in a readily reconstructable location, marginal resection with structural allograft or autograft reconstruction is preferable.

Patient's with recurrent lesions should have follow-up CT scans of the chest to detect pulmonary nodules. Pulmonary nodules should be excised.

Fink BR, Temple HT, Chiricosta FM, Mizel MS, Murphey MD. Foot Ankle Int. 1997
Apr;18(4):236-42. Chondroblastoma of the foot.

Click on an image to enlarge
(All images © bonetumor.org)