Perineural invasion

Micrograph showing a prostate cancer (conventional adenocarcinoma) with perineural invasion. H&E stain.

In pathology, perineural invasion, abbreviated PNI, refers to cancer spreading to the space surrounding a nerve. It is common in head and neck cancer, prostate cancer and colorectal cancer.

Significance

Cancers with PNI usually have a poorer prognosis, as PNI is thought to be indicative of perineural spread, which can make resection of malignant lesions more difficult.

Prostate cancer

In prostate cancer, PNI in needle biospies is poor prognosticator; however, in prostatectomy specimens it is unclear whether it carries a worse prognosis.

In one study, PNI was found in approximately 90% radical prostatectomy specimens and, PNI outside of the prostate, especially, was associated with a poorer prognosis. However, there exists controversies about whether PNI has prognostic significance toward cancer malignancy.

Additional images

• Perineural invasion prostate high mag.jpg

  Micrograph demonstrating perineural invasion. HPS stain.

See also

• Lymphovascular invasion
• Malignancy