Key Points
• A lucent lesion with central calcification in the anterior os calcis is considered pathognomonic of an intraosseous lipoma.
• Confirmation of fat composition of a bone lesion by MR imaging or CT is usually sufficient to confirm the diagnosis of a lipogenic tumour of bone without the need to biopsy.
• Although other lesions may contain fat, they are nearly always benign lesions.
• Sinister features which merit biopsy include the presence of cortical destruction and an associated soft tissue mass.