Perineural Invasion of Cutaneous Squamous Cell Carcinoma and Basal Cell Carcinoma: Raising Awareness and Optimizing Management

Abstract

Perineural invasion (PNI) by cutaneous squamous cell carcinoma (CSCC) and basal cell carcinoma (BCC) is an infrequent but not rare complication of traditionally low-morbidity skin cancers that can lead to catastrophic sequelae; 2.5% to 14% of CSCC and approximately 3% of BCC exhibit PNI. Tumors with PNI tend to be larger, have greater subclinical extension, have a higher rate of recurrence, and have a greater risk of metastases. Tumors with PNI may result in major neurologic deficits. To review current recommendations for the management of PNI and to evaluate a treatment strategy involving excision using Mohs micrographic surgery (MMS) followed by adjunctive radiotherapy. Cases of PNI treated with MMS and radiotherapy were reviewed for recurrence, disease-free follow-up, and adverse events. Twelve patients with incidental PNI treated with MMS and adjunctive radiotherapy are presented. After 3 to 32 months of follow-up, there had been no recurrences. Adverse events from radiotherapy were minor and self-limited. The use of adjunctive radiotherapy in these patients remains controversial. When managing superficial skin tumors with PNI, a multidisciplinary team including a cutaneous surgeon and a radiation oncologist familiar with PNI is recommended.