Diagnosis and Literature Review of Chondromyxoid Fibroma – A Pathological Puzzle

INTRODUCTION: Chondromyxoid fibroma (CMF) is a benign rare bone tumor of slow-growing nature arising from chondroblastic derivation. CMF in most of the cases is a diagnosis of exclusion, and in this case report, we differentiate the histological and radiological findings of CMF and difficulties in diagnosis of CMF from potential differential diagnosis. CASE REPORT: A 38-year-old female patient presented with a history of limping for 5 months and on evaluation revealed an expansile osteolytic lesion in fibular head with septations and soft tissue component. Excision biopsy was done. Histological examination revealed a cellular neoplasm arranged as vague nodules in chondroid background with occasional mitotic figures and giant cells in periphery without any calcification. To rule out chondroblastoma, S-100 and epithelial markers were done which was negative establishing diagnosis of CMF by exclusion. CONCLUSION: CMF is often misdiagnosed being a radiological and pathological mimicker. Histology remains key to diagnosis. En bloc resection remains the mainstay of management in expendable bone-like fibula.