Basal cell carcinoma with perineural invasion: reexcision perineural invasion?

Background: Perineural invasion (PI) in basal cell and squamous cell carcinomas, especially of the head and neck, has been reported to indicate an increased morbidity. Reexcision perineural invasion (RPI), a benign mimic of tumoral perineural invasion, may present a difficult histologic differential diagnosis. Methods: We surveyed the medical literature for PI occurring in basal cell carcinomas to investigate the degree to which the reported cases occurred in reexcision specimens vs. primary biopsy specimens. Results: We found large retrospective studies of 14,120 basal cell carcinomas evaluated for PI in which 310 cases of PI were identified (2.2%), and 20 sporadic case reports of basal cell carcinomas with PI. Of 310 cases of basal cell carcinoma with PI, 196 (63%) were in reexcision specimens. Of 20 sporadic reports, 17 (85%) were in reexcision specimens. Conclusion: The high percentage of PI occurring in reexcision specimens vs. primary excisions may indicate that many of the reported cases of basal cell carcinomas with PI are actually examples of RPI.