We thank our colleagues for their interest in our paper “Intraosseous lipomas originating from simple bone cysts.”

Our colleagues rightly assert that cases of intraosseous cysts in the calcaneum healing as fatty lesion have been described before and we specifically repeatedly and explicitly quote the paper from Malghem et al. from 2017.

While there were case reports of cystic lesions healing with fatty change, we tried to do establish whether this response is a (possibly rare) event or the rule. We do not want to generalise based on a number of case reports.

To achieve this, we looked at all of our cases of simple bone cyst and fatty intraosseous lesions and their behaviour over time.

We found that cystic lesions show fatty healing over time, while primary fatty lesions were static (contrary to other studies proposing but not proofing cystic degeneration of fatty lesions over time).

Our study included lesions in various anatomical locations rather than just the calcaneus.

Based on these findings, we proposed that fatty transformation is likely the rule rather than the exception for the healing of simple bone cysts. The findings also suggest that intraosseous lipomas often are the result of healing cysts; we found no case of lipoma undergoing cystic change.