Intracranial spread of squamous carcinoma along the trigeminal nerve.

Two patients with intracranial dissemination of squamous carcinoma along the trigeminal nerve had facial dysesthesias mistakenly diagnosed as tic douloureux. In one case, tumor originated in the skin of the lateral canthus and spread along an orbital nerve to involve the cavernous sinus and Gasserian ganglion. In the other, the primary site was the retromolar trigone, with preponderantly deep intraosseous growth. Perineural spread occurred along the inferior alveolar nerve to eventually involve the facial and the ocular motor nerves. Such neurotropic spread of tumors is unfamiliar to many clinicians, yet early diagnosis may be life-saving. If intracranial foramina have not been transgressed, surgery and radiotherapy have been curative; otherwise, treatment is largely palliative. Adequate initial treatment of the primary lesion would seem to be the best preventive measure. Treatment of recurrent lesions should include consideration of neural invasion.