Chondrosarcoma proximal tibia secondary to chondromyxoid fibroma: A rare case report

Introduction: Benign cartilage tumours with malignant transformation are reported very few. Aiming to report a secondary chondrosarcoma in proximal tibia after chondromyxoid fibroma: a rare entity with limited experience of management.

Case presentation: we present a challenging case of secondary chondrosarcoma of proximal tibia in surgically managed chondromyxoid fibroma. Presented to us with recurrent swelling and pain in proximal leg. The diagnosis was confirmed on biopsy and high-grade chondrosarcoma was found. Multidisciplinary approach was taken and treated with neoadjuvant chemotherapy and surgical excision was done with biological reconstruction with fibular strut and iliac crest grafting and soft tissue coverage with medial gastrocnemius muscle flap. The patient achieved good functional outcome with no recurrence at 2-year follow-up.

Discussion: Benign cartilage tumours mistreated might result in recurrence or malignant transformation. Treatment strategies vary with grade of malignant cartilaginous tumours with low grade chondrosarcoma treated with extensive intralesional curettage followed by local adjuvant treatment and high grade managed with wide excision or amputation.

Conclusion: Even though chondromyxoid fibroma is uncommon and benign, it has a high chance of recurrence and perhaps developing into chondrosarcoma. For better results and to stop progression, appropriate surgical intervention are essential.