Perineural spread of squamous cell carcinoma involving trigeminal and facial nerves.

Perineural spread of squamous cell carcinomas in the orofacial region predominantly involves the trigeminal and facial nerves. Central spread, particularly along the trigeminal nerve, produces sensory impairment and involvement of other divisions through invasion of the gasserian ganglion, as illustrated in these case reports. Early diagnosis and medical referral is important because central invasion has a poor prognosis.