Squamous Cell Carcinoma in Lesions of Disseminated Superficial Actinic Porokeratosis: A Report of Two Cases

To the Editor.—  Since the 1966 report by one of us (M.E.C.)¹ of 12 patients with multiple superficial lesions of porokeratosis in sun-exposed areas and the proposed designation of disseminated superficial actinic porokeratosis (DSAP) as a variant of porokeratosis,^2-4 the potential for a premalignant tendency has been debated. In 1982, Shrum et al⁵ described a patient who developed squamous cell carcinoma in a lesion of DSAP. We describe herein two other patients with squamous cell carcinomas occurring within DSAP lesions.

Report of Cases.—Case 1.—  A 47-year-old woman with a light complexion first presented in 1966. She had a twoyear history of the development of multiple lesions on exposed areas. Clinically, the lesions were a superficial type of porokeratosis and results of a biopsy showed a small, not very prominent, cornoid lamella consistent with DSAP.Over the years, the DSAP lesions increased in number; they