Perineural Invasion in Cutaneous Squamous Cell Carcinoma.

Cutaneous squamous cell carcinoma is sometimes characterized by an increased risk of locoregional recurrence and occasionally distant metastasis. Several clinical and pathological factors, including perineural invasion, have been shown to have prognostic value in this setting. Perineural invasion, that is, the spread of tumor cells into the space surrounding a nerve, is usually an incidental finding. In the presence of symptoms or radiographic evidence of perineural spread, the diagnosis is clinical perineural invasion, which is associated with an increased risk of local recurrence and mortality.