Perineural Invasion of Oral Squamous Cell Carcinoma: A New Hurdle for Surgeons.

The high rate of mortality associated with cancer is due to its inherent nature to metastasize. Perineural invasion (PNI) is a relatively rare mode of metastasis, and a distinct pathologic entity that can be observed in the absence of lymphatic or vascular invasion which is still shrouded by mystery. PNI is a marker of poor prognosis.