Clear Cell Chondrosarcoma Masquerading as a Benign Lesion of Bone: A Rare Case Report

Clear Cell Chondrosarcoma (CCC) accounts for about 2% of all chondrosarcoma subtypes and typically presents in individuals during their third to fourth decades of life. This type of tumour most commonly arises in the proximal epiphyseal region of the femur, followed by the humerus, tibia, and small bones. It is frequently observed in males and often manifests as a painful lesion that reduces mobility, leading to misdiagnosis as a benign condition. Histopathologically, the tumour is characterised by round to polygonal cells having clear to vacuolated cytoplasm, arranged in diffuse sheets and lobules, accompanied by reactive woven bone formation and rare mitotic activity. Due to high recurrence rates associated with conservative treatments such as curettage, wide excision of the affected bone followed by reconstruction is recommended. We report a rare case of CCC involving the proximal end of the femur in a 30-year-old male patient who presented with right hip pain for five months. Radiological investigations revealed a well-defined osteolytic lesion confirmed by MRI. Biopsy showed clear cells, reactive woven bone and a few multinucleated giant cells. Herein, we discuss the several differentials possible and discuss the challenges encountered during final diagnosis.