In pathology, perineural invasion, abbreviated PNI, refers to the invasion of cancer to the space surrounding a nerve. It is common in head and neck cancer, prostate cancer and colorectal cancer.
Unlike perineural spread (PNS), which is defined as gross tumor spread along a larger, typically named nerve that is at least partially distinct from the main tumor mass and can be seen on imaging studies, PNI is defined as tumor cells infiltrating small, unnamed nerves that can only be seen microscopically but not radiologically and are often confined to the main tumor mass. The transition from PNI to PNS is not precisely defined, but PNS is detectable on MRI and may have clinical manifestations that correlate with the affected nerve.[1]
- ^ Medvedev, Olga; Hedesiu, Mihaela; Ciurea, Anca; Lenghel, Manuela; Rotar, Horatiu; Dinu, Cristian; Roman, Rares; Termure, Dragos; Csutak, Csaba (2021-06-29). "Perineural spread in head and neck malignancies: imaging findings - an updated literature review". Bosnian Journal of Basic Medical Sciences. doi:10.17305/bjbms.2021.5897. ISSN 1840-4812. PMC 8860315. PMID 34255618.
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