Perineural spread of tumour is a form of local invasion in which primary tumours cells spread along the tissues of the nerve sheath. It is a well-recognised phenomenon in head and neck cancers.
An important distinction has to be made between perineural invasion (PNI) and perineural spread (PNS). The former is a histological finding of tumour cell infiltration or associated with small nerves that cannot be radiologically imaged, while the latter is macroscopic tumour involvement along a nerve extending away from the primary tumour; this can be radiologically apparent. A third term, neurotropism, simply means that a tumour has an affinity for growth along nerves.
Perineural tumour spread is more frequently associated with 1,2,5:
- mucosal/cutaneous squamous cell carcinoma
- oral cavity/laryngeal (2-30%) > cutaneous (3-8%)
- most common overall 5
- salivary gland carcinoma
- mucosal/cutaneous basal cell carcinoma (2-5% demonstrate perineural tumour spread) 4
- meningioma (rare) 6
Perineural tumour spread could be characterised as nerve thickening, widening of the neural foramen, loss of the fat surrounding the nerve and enhancement of the nerve following contrast administration.
- 1. Maroldi R, Farina D, Borghesi A et-al. Perineural tumor spread. Neuroimaging Clin. N. Am. 2008;18 (2): 413-29, xi. doi:10.1016/j.nic.2008.01.001 - Pubmed citation
- 2. VandeVyver V, Lemmerling M, Van Hecke W et-al. MRI findings of the normal and diseased trigeminal nerve ganglion and branches: a pictorial review. JBR-BTR. 2007;90 (4): 272-7. Pubmed citation
- 3. Johnston M, Yu E, Kim J. Perineural invasion and spread in head and neck cancer. Expert Rev Anticancer Ther. 2012;12 (3): 359-71. doi:10.1586/era.12.9 - Pubmed citation
- 4. Gaddikeri S. Perineural Invasion of Skin Cancers in the Head and Neck: An Uncommon Phenomenon Revisited. Otolaryngology.2014 (03): . doi:10.4172/2161-119X.1000169
- 5. Paes FM, Singer AD, Checkver AN et-al. Perineural spread in head and neck malignancies: clinical significance and evaluation with 18F-FDG PET/CT. Radiographics. 2013;33 (6): 1717-36. doi:10.1148/rg.336135501 - Pubmed citation
- 6. Walton H, Morley S, Alegre-Abarrategui J. A rare case of atypical skull base meningioma with perineural spread. (2015) Journal of radiology case reports. 9 (12): 1-14. doi:10.3941/jrcr.v9i12.2648 - Pubmed