**Note 1:** Physician statement of microscopically confirmed perineural invasion can be used to code this data item when no other information is available.
**Note 2:** Code the presence or absence of perineural invasion by the primary tumor as documented in the pathology report.
**Note 3:** Information on **presence** of perineural invasion can be taken from either a biopsy or resection. Absence of perineural invasion can only be taken from a surgical resection pathology report.
**Note 4:** Code 9 if surgical resection of the primary site is performed and there is no mention of perineural invasion.