Rapid Forehead Ossification due to a Subperiosteal Hematoma in a Patient With Neurofibromatosis Type 1

Rapid ossification due to a subperiosteal hematoma in extremities has occasionally been documented in patients with neurofibromatosis type 1, but it has not been reported in the maxillofacial region. The authors present the first case of a subperiosteal hematoma in the forehead. A 36-year-old man presented with a rapidly swelling firm, fixed, 8×10 cm forehead mass. It became evident shortly after a fine-needle aspiration biopsy. Computed tomography imaging 2 months after the biopsy showed a hematoma that was encapsulated by a surrounding layer of ossification. Magnetic resonance imaging displayed a fluid-fluid level under the ossified area. These characteristic images led us to diagnose this rare lesion as a subperiosteal hematoma with ossification. Rapid ossification is a characteristic imaging finding of subperiosteal hematoma, which makes definitive diagnosis easy. It becomes imperative to underscore the potential risks of fine-needle aspiration in proximity to the periosteum in patients with neurofibromatosis type 1.