Abstract

Perineural invasion (PNI) is the process of neoplastic invasion of nerves and is an under-recognized route of metastatic spread. It is emerging as an important pathologic feature of many malignancies, particularly in head and neck cancers, associated with decreased survival, increased and earlier recurrence. PNI status often significantly affects surgical strategies and adjuvant treatments in head and neck cancers. MRI has been the gold standard imaging modality for the evaluation of PNI. FDG PET/CT has been increasingly used for staging and restaging head and neck cancers. Beyond locoregional disease and lymph node metabolic characterization, different PET imaging patterns suggesting PNI can also be identified. Our goal is to demonstrate different examples of PNI visualized by PET/CT and the correlation with other cross sectional imaging modalities, such as CT and MRI.