What does "perineural invasion" suggest in tumor pathology?

Perineural invasion refers to the presence of cancer cells within the perineural space, which is the area surrounding a nerve. This phenomenon is significant in tumor pathology as it often indicates a more aggressive tumor behavior and can suggest that the tumor is utilizing nerve pathways for growth and dissemination. The involvement of nerve sheaths can be associated with pain and may influence treatment decisions, as it often indicates a higher potential for local recurrence and can complicate surgical resection.

In addition, perineural invasion is especially noted in certain types of cancers, such as prostate carcinoma and pancreatic adenocarcinoma, where the proximity to nerves provides a means for the tumor to grow along these structures, directly affecting prognosis and management strategies. This mechanistic understanding highlights the importance of identifying perineural invasion during histopathological assessment.