An unusual cause for trismus caused by mandibular coronoid osteoma: a case report
A 26-year-old female patient visited the Department of Oral Medicine and Radiology, Subharati Dental College complaining of gradual reduction of her mouth opening over a period of two years and associated difficulty in chewing. There was no history of trauma to the oral and maxillofacial region. The maximum mouth opening was about 20 mm with deviation of the mandible to the right side while opening (). Mild tenderness was noticed over the right temporomandibular joint area. On intraoral examination, a bony mass in the coronoid process could be palpated along with tenderness in the region.\nA panoramic radiograph (Vatech Inc., Hwaseong, Korea) () revealed a radiopaque mass about 1.5 cm×1 cm extending from the right coronoid process. A non-contrast computed tomogram (CT/e GE, Fairfield, CT, USA) of the region revealed a bony outgrowth associated with the right coronoid process projecting anteromedially with a short and narrow stalk causing erosion of the posterolateral wall of the right maxillary sinus (). A three-dimensional CT image of the region also showed the presence of a coronoid mass (). Based on the clinical and radiographic findings and considering the history of slow progression, a clinical diagnosis of benign osseous neoplasm of the right mandibular coronoid process was made. Under general anaesthesia, using an intraoral approach, excision of the mass along with the coronoid process was performed. The surgical specimen comprised a mushroomshaped bony mass measuring around 2.5 cm×3 cm×3 cm in size (). On microscopic examination, the specimen revealed a highly cellular collagenized stroma with abundant interconnected bony trabeculae (). Higher magnification revealed cancellous lamellated bony trabeculae with lacunae containing osteocytes with osteoblastic rimming (). Based on these features, the final diagnosis of osteoma of the right mandibular coronoid was made, and the patient was advised to perform mouth opening exercises and physiotherapy. The post-operative recovery of the patient was satisfactory and the patient could open her mouth up to 35 mm after one month and one year of follow-up (). The two-year follow-up of the patient showed no signs of recurrence following surgery.