Chondromyxoid Fibroma of Distal Phalanx of the Great Toe: A Rare Clinical Entity.

Chondromyxoid fibroma is a rare benign tumor of cartilaginous origin with myxoid and fibrous components. It accounts for approximately 1% of bone tumors. Metaphysis of long bones is the most common location of this tumor. However, there a few case reports of this tumor arising from epiphysis of short tubular bones of the hand and feet. An 11-year-old girl presented to our OPD with complaints of pain and a gradually progressive swelling of the right great toe. On examination, the swelling was diffuse with no signs of inflammation. X-ray examination revealed a well-defined, longitudinally oval lytic lesion in the right distal phalanx of great toe, involving the growth plate and, eroding the medial cortex. Computed tomography (CT) scan did not show any evidence of calcification, septations or involvement of soft tissue. Open biopsy and curettage was done and the specimen was sent for histopathological examination. Histopathological examination (HPE) showed a lobular pattern consisting of myxomatous stroma and immature cartilaginous cells in lacunae. The lobules were separated by fibrous septae. It was reported to be Chondromyxoid fibroma. The patient presented six months later with persisting pain and X-ray showed recurrence of the tumor. Hence, complete excision of the tumor was done and the defect was filled using synthetic bone graft. At six months follow up, the patient did not complain of pain and X-rays showed signs of bone formation with incorporation of the graft. Chondromyxoid fibroma is a low grade tumor, which may demonstrate nuclear atypia histologically and mimic chondrosarcoma. Differentiating these two is of paramount importance to avoid over-diagnosis and aggressive treatment. Recurrence is common with marginal excision and especially in younger patients like in our case. Complete resection is the mainstay of management. Long-term follow up of patients is necessary to watch for malignant transformation, a rare complication. Chondromyxoid fibroma is an extremely rare neoplasm of bone. There are no specific radiologic features, and histopathology provides a definitive diagnosis. It should be considered in differential diagnosis of lytic lesion, and differentiated from other tumors, especially from chondrosarcoma to treat the patient appropriately.