Imaging of perineural spread in head and neck tumours

Perineural tumour spread refers to a contiguous neoplastic extension along a nerve. As it may be clinically silent, imaging plays a pivotal role in the evaluation and delineation of perineural infiltration in head and neck malignancies, which in turn affects treatment planning. This article focuses on the imaging features of perineural spread of head and neck tumours. The important potential perineural pathways and the possible underlying pathogenesis of this phenomenon are also reviewed.