Incidence of perineural invasion in histologically aggressive types of basal cell carcinoma.

Basal cell carcinoma is generally an indolent form of skin cancer. Morpheaform, infiltrative, and sclerosing types are more aggressive tumors. The incidence of perineural invasion in aggressive types of basal cell carcinoma has not been previously described. We studied aggressive basal cell carcinomas for the presence of perineural invasion. Between 1995 and 1998, the histopathologic diagnosis of basal cell carcinoma was made on 5,097 specimens at Dartmouth-Hitchcock Medical Center. Of this total, 507 were classified as sclerosing, infiltrative, or morpheaform. Perineural invasion was found in 15 of the 507 cases. Of these 15 cases, 12 were from the face, and 3 from the back; 13 were recurrent, and 2 were primary lesions. The mean age of patients at diagnosis was 71 years. We found 9.9% of all basal cell carcinomas at our institution to be aggressive types. We found an incidence of perineural invasion of 3% in the aggressive basal cell carcinoma types. This incidence approaches that reported by others for cutaneous squamous cell carcinomas.