A Soft Tissue Osteochondrolipoma of the Lateral Ankle: A Case Report and Clinical Insight.

Tumors of the foot and ankle are uncommon, accounting for approximately 4%-10% of all musculoskeletal tumors; most are benign soft-tissue lesions. Osteochondrolipoma is an exceptionally rare histological variant of lipoma characterized by mature adipose tissue with cartilaginous and osseous differentiation. It is typically reported in the head, neck, and upper extremities, whereas its occurrence in the lower extremity, particularly the hindfoot, is exceedingly rare. We report a case of osteochondrolipoma of the lateral aspect of the hindfoot of a 54-year-old female who presented with a painless, slowly enlarging mass causing difficulty with footwear. Imaging demonstrated a well-defined, heterogeneous soft tissue lesion with ossified components, without bone attachment. Complete surgical excision was performed. Histopathological examination revealed mature adipose tissue interspersed with hyaline cartilage and mature bony trabeculae with evidence of endochondral ossification, confirming the diagnosis of osteochondrolipoma. The postoperative course was uneventful. At 3 months of follow-up, the patient reported complete resolution of symptoms and no difficulty wearing footwear. Functional outcome improved, with the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score increasing from 81 preoperatively to 88. No clinical evidence of recurrence was observed. Osteochondrolipoma is a benign entity with an excellent prognosis after complete excision. Given its rarity in the hindfoot and its potential to mimic other calcified soft tissue tumors, clinicians and pathologists should consider osteochondrolipoma in the differential diagnosis of well-circumscribed ossified masses of the foot and ankle.