**5. Diagnosis**

The diagnosis of HNOS is based on radiological and pathological findings. Most tumors arise within the medullary cavity of the affected bone, with rare examples developing on the bone surface [1].

It constitutes a diagnostic challenge due to its rare occurrence, diverse clinical presentation, and the fact that typical radiological features may not always be present, which can often lead to misinterpretation of lesions or delay in diagnosis.
