Frederic E. Mohs, M.D. and the history of zinc-chloride

Publication date: Available online 28 December 2017
Source:Clinics in Dermatology
Author(s): Charles DePaolo
The history of ZnCl2 therapy prior to and including Frederic E. Mohs' (1910–2002) early contributions to dermatologic oncology is presented. In 1932, Mohs devised a method of cutaneous surgery that employed zinc-chloride paste (ZCP) to devitalize basal (BCC) or squamous (SCC) cell carcinoma. Because ZnCl2 coagulates malignant tissue without destroying cellular architecture, he described the surgery and its preservative effect as the fixed-tissue method. This method involved the serial removal of devitalized malignant tissue and the freezing and histologic examination of each layer; the process was continued until a cancer-free plane was reached. In 1953, a modified version of the micrographic system, the fresh-tissue method, was introduced. For improved efficiency, Mohs retained the systematic mapping of a neoplasm but eliminated the chemical escharotic. While the fresh-tissue method has become the preferred treatment mode, ZCP therapy remains in use today. Although the history of Mohs micrographic surgery is well documented, its background has not received sufficient attention. This paper surveys the chemical synthesis of ZnCl2, the formulation of ZCP as a cutaneous escharotic, and the extent to which Mohs' method compares to those of nineteenth and of early-twentieth-century predecessors.