An unusual cause of facial trismus in a child: report of case.

Nasopharyngeal carcinoma should be considered in the differential diagnosis of facial pain, especially in patients of Asian descent. The foregoing case describes an unusual cause of a symptom often associated with temporomandibular joint dysfunction. It also emphasizes the need to eliminate an underlying neoplastic process when dealing with patients who have temporomandibular joint dysfunction or who have atypical facial pain. Malignancies of the temporomandibular joint and the periarticular area, although rare, do occur. This case shows the usefulness of computed tomography in the evaluation of a patient with temporomandibular joint dysfunction.