Myositis Ossificans of the Temporalis Muscle Following Neurosurgical Intervention: A Report of a Rare Case and Literature Review.

Myositis ossificans (MO) is a rare benign condition characterized by heterotopic bone formation within soft tissues, with masticatory muscle involvement being exceptionally uncommon. This case report describes a 45-year-old male patient who developed progressive trismus and a preauricular mass six months after right frontotemporal craniotomy for meningioma resection. Imaging revealed an ossified lesion in the temporalis muscle, consistent with post-traumatic MO. Surgical management involved zygomatic arch osteotomy and coronoidectomy, restoring intraoperative mouth opening to 23 mm. Histopathology confirmed mature lamellar bone, supporting the diagnosis. At six-month follow-up, the patient achieved full functional recovery with no recurrence. This case highlights the importance of considering MO in post-craniotomy trismus and the role of timely surgical intervention in established lesions.