Case report 713. Chondromyxoid fibroma of the third metatarsal

Recurrent chondromyxoid fibroma of the distal femur treated with percutaneous cryoablation

Chondromyxoid fibroma is a rare, benign tumor of the bone with excellent prognosis but a high rate of recurrence. We report a patient presenting with pain and a history of chondromyxoid fibroma of the distal left femur previously treated with multiple prior curettage and bone graft procedures. Magnetic resonance imaging and histopathology indicated a recurrence of tumor. Due to the small size of the tumor recurrence and challenges associated with prior open surgery, the patient underwent cryoablation of the lesion with computed tomography guidance. Follow-up 18 months later indicated a resolution of pain and improvement on magnetic resonance imaging, and no concerns after 20 months. To our knowledge, this is the first reported case of chondromyxoid fibroma treated with cryoablation. This case suggests cryoablation could be considered in the setting of recurrent chondromyxoid fibroma for local tumor control.

Chondromyxoid fibroma of the foot and ankle: 40 years' Scottish bone tumour registry experience

Ten cases of histologically proven chondromyxoid fibroma (CMF) of the foot and ankle with a mean follow-up of 6.1 years were retrospectively reviewed using the Scottish Bone Tumour Registry. The patients' mean age was 19 years; there were six males and four females. The anatomical locations were five phalangeal, three metatarsal, one tarsal affecting body of os calcis and one distal tibial. The median delay in presentation was 4.5 months. The modes of presentation were pain only (n=4), painful lump (n=4) and painless lump (n=2). The typical radiological finding was an expansile, lobulated, cystic lesion. Cortical erosion was documented in 80% patients. In four cases, curettage alone was carried out, while five patients underwent curettage along with autogenous bone grafting. One patient with distal phalangeal CMF had a primary toe amputation. Two patients had recurrences 9 and 16 months after their initial curettage. Both of them were males with proximal phalangeal CMF, associated with cortical erosion. Foot and phalangeal CMF initially treated with curettage only should be closely followed up, as we observed a 20% recurrence rate within a 2-year period. Cases featuring cortical erosion require thorough curettage and may require autogenous bone grafting to prevent fracture.