Introduction: Subperiosteal hematoma (SPH) is a rare complication of neurofibromatosis type 1 (NF-1) which can be presented spontaneously or after a minor trauma a painful or painless growing lesion.
Presentation Of Case: Here, we presented a 10-year-old boy, a known case of NF-1, who presented with a painless growing leg lesion. The bony wall cystic lesion was suggested based on radiologic and pathologic investigation.