title: Perineural invasion of cutaneous squamous cell carcinoma and basal cell carcinoma: raising awareness and optimizing management.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  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.
  
  
  METHODS
  Cases of PNI treated with MMS and radiotherapy were reviewed for recurrence, disease-free follow-up, and adverse events.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Division of Dermatology, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA. david.geist@umassmemorial.org
authors.forename: David E
authors.initials: DE
authors.lastname: Geist
authors.forename: Maria
authors.initials: M
authors.lastname: Garcia-Moliner
authors.forename: Markus M
authors.initials: MM
authors.lastname: Fitzek
authors.forename: Hannah
authors.initials: H
authors.lastname: Cho
authors.forename: Gary S
authors.initials: GS
authors.lastname: Rogers
mesh_terms: D000328:Adult; D020330:Bell Palsy / Q000209:etiology*; D002280:Basal Cell Carcinoma / Q000150:complications* / Q000473:pathology / Q000532:radiotherapy / Q000628:therapy*; D002294:Carcinoma, Squamous Cell / Q000150:complications* / Q000473:pathology / Q000532:radiotherapy / Q000628:therapy*; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D015580:Mohs Surgery; D009361:Neoplasm Invasiveness; D009378:Neoplasms, Multiple Primary / Q000150:complications* / Q000473:pathology / Q000532:radiotherapy / Q000628:therapy*; D010525:Peripheral Nerves; D012878:Skin Neoplasms / Q000150:complications* / Q000473:pathology / Q000532:radiotherapy / Q000628:therapy*