A Solitary Large Calcaneal Osteochondroma in a Skeletally Mature Patient: Case Report

Calcaneal osteochondromas are rare, particularly in skeletally mature adults where continued growth often raises suspicion for malignant transformation. This case highlights one of the largest benign calcaneal osteochondromas reported in an adult, demonstrating extensive growth after epiphyseal closure without malignant change.

A 38-year-old male presented with an 8-year history of left foot pain and a progressively enlarging plantar mass for 7 years. The mass enlarged over 5 years and stabilized for the last 2 years. Examination revealed a hard, tender, plantolateral swelling with overlying hyperkeratosis. Radiographs showed a large sessile bony mass arising from the plantar calcaneus. En bloc excision was performed. The mass measured 7.5 × 5 × 3 cm with a cartilage cap of 9 mm. Histopathology confirmed benign osteochondroma with no malignant transformation. The patient recovered uneventfully and remained recurrence-free at 24 months.

Large calcaneal osteochondromas can present in adulthood and may grow after skeletal maturity without malignant change. Surgical excision provides excellent outcomes with negligible recurrence when margins are adequate.