Adenoid Cystic CA : Perineural Invasion

Perineural invasion is a consistent and a prominent feature which is almost a requirement for the diagnosis of adenoid cystic carcinoma. It is related to the overexpression of brain derived neurotrophic factor by the tumor cells. Perineural invasion is often the reason the tumor has infiltrated beyond grossly visible margins, resulting in positive resection margins and very high recurrence rates.