Patterns of incidental perineural invasion and prognosis in cutaneous squamous cell carcinoma: A multicenter, retrospective cohort study

To the Editor: Perineural invasion (PNI) is rare and usually incidental in cutaneous squamous cell carcinoma (SCC), with an incidence of 2.5% to 14%.1 Incidental PNI is associated with poor prognosis in cutaneous SCC,2 and some evidence suggests its outcome differs, depending on the PNI pattern. We evaluated patterns of incidental PNI, using a multicenter retrospective cohort of 140 cutaneous SCCs with incidental PNI to determine the influence of nerve involvement on cutaneous SCC prognosis.Dr Canueto is partially supported ~ by grants PI18/000587 (Instituto de Salud Carlos III, cofinanced by Fondo Europeo de Desarrollo Regional) and GRS 1835/A/18 (Gerencia Regional de Salud de Castilla y Leon)