Osteochondroma of the calcaneus

Osteochondroma is a benign osteocartilaginous lesion characterized by a bony projection covered by a cartilage cap. Although it is one of the most common benign bone tumors, its occurrence in the calcaneus is uncommon. A lesion arising from the posterosuperior calcaneus may clinically resemble a Haglund deformity and may remain difficult to distinguish from other causes of posterior heel prominence. We report the case of a patient with insulin-treated diabetes mellitus and diabetic peripheral neuropathy with neuropathic osteoarthropathy who presented with painless, progressive deformities of both feet evolving over six years. The most prominent lesion was located on the posterosuperior aspect of the right calcaneus and caused difficulty wearing shoes because of mechanical conflict. Plain radiography demonstrated marked hypertrophy of the posterosuperior calcaneus without bone lysis or sclerosis. Computed tomography demonstrated an osseous formation measuring approximately 30 mm in anteroposterior diameter. Magnetic resonance imaging showed a lobulated osteocartilaginous-appearing formation measuring approximately 28 × 16 mm arising from the posterosuperior calcaneus and extending anteriorly, with enlargement around the insertion of the Achilles tendon. The imaging characteristics were considered most compatible with an osteochondroma. Calcaneal osteochondroma is a rare cause of posterior heel deformity and may mimic a Haglund deformity or another calcaneal exostosis. Cross-sectional imaging, particularly MRI, is useful for characterizing the lesion and assessing its relationship with adjacent soft tissues. In an asymptomatic patient with diabetes and peripheral neuropathy, conservative management with appropriate footwear and regular skin surveillance may be preferable when there is no ulceration, infection, significant pain, or radiological evidence of aggressive behavior.