Perineural Invasion
Also written as: PNI — Perineural Invasion
The spread of tumour cells along or around nerve sheaths, a pathological finding that significantly worsens prognosis in oral and maxillofacial malignancies.
Full Definition
Perineural invasion (PNI) describes the process by which cancer cells track along the perineural space surrounding nerves, allowing tumour spread beyond the primary site. In oral maxillofacial pathology, PNI is a critical prognostic variable reported in surgical pathology documents and must be explicitly stated as present or absent. It is particularly associated with adenoid cystic carcinoma, squamous cell carcinoma, and salivary gland malignancies. Editors should not confuse PNI with lymphovascular invasion (LVI), which is a distinct finding. Both findings should be reported separately in synoptic pathology reports.
Usage
Usage note: Must be distinguished from lymphovascular invasion in synoptic reports. Abbreviate as PNI only after first full use.
In Context
- "Perineural invasion was identified in three of five tissue sections, prompting adjuvant radiotherapy." — Multidisciplinary team report
- "The synoptic checklist requires editors to verify that perineural invasion status is explicitly recorded as present, absent, or indeterminate." — Editorial style guide