Perineural Spread of Tumor in the Skull Base and Head and Neck.

Perineural tumor spread (PNS) is a well-recognized entity in head and neck cancers and represents a mode of metastasis along nerves. The trigeminal and facial nerves are most affected by PNS, and their connections are reviewed. MRI is the most sensitive modality for detecting PNS, and their anatomy and interconnections are reviewed. MRI is the most sensitive modality for detecting PNS, and imaging features of PNS and important imaging checkpoints are reviewed. Optimal imaging protocol and techniques are summarized as well as other entities that can mimic PNS.