perineural invasion
Also written as: PNI — perineural invasion
Tumor spread along nerve pathways, an important histologic feature indicating aggressive disease behavior.
Full Definition
A histopathologic finding characterized by tumor cells tracking along nerve sheaths, often extending beyond the primary tumor boundaries. Perineural invasion is particularly common in adenoid cystic carcinomas and aggressive squamous cell carcinomas of the head and neck. This pattern of spread is associated with increased risk of local recurrence, distant metastasis, and poorer overall survival. The presence of perineural invasion often influences treatment decisions, potentially indicating the need for wider surgical margins or adjuvant radiation therapy.
Usage
Usage note: PNI is commonly used abbreviation in pathology reports.
In Context
- "Histopathology revealed extensive perineural invasion involving the trigeminal nerve branches." — Pathology report
- "The presence of perineural invasion prompted consideration of adjuvant radiation therapy." — Treatment planning documentation