Perineural spread (PNS) of tumour

Perineural spread (PNS) 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).  PNI is a histological finding of tumor cells infiltrating or associated with small nerves (which cannot be radiologically imaged).  PNS 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:

Radiographic features


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 after contrast administration. 

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Article Information

rID: 33252
Section: Pathology
Tag: cases
Synonyms or Alternate Spellings:
  • Perineural spread
  • PNS
  • Perineural tumor spread

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    Case 1: cutaneous SCC and infraorbital nerve
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