Beyond the conventional routes of direct extension, hematogenous, and lymphatic spread, tumors may also propagate along peripheral nerves, a process known as perineural spread (PNS). Historically identifiable only on pathology, PNS can now be detected using CT, MRI, and PET/CT. Accurate diagnosis requires a thorough understanding of the relevant anatomy and familiarity with characteristic routes of spread, which vary according to tumor type and location. PNS is well-recognized in head and neck cancers, where radiologists are highly familiar with detailed neural anatomy. Importantly, PNS can sometimes represent the sole route of tumor extension beyond the primary site.