Cysts

Abstract

Cysts of the skin are tumors or tumor-like alterations that show one or more cavities clinically or histologically. Real cysts are surrounded by an epithelial cyst wall; pseudocysts are made up of compressed connective tissue or granulation tissue. The cyst content is of variable viscosity and consistency, ranging from calcified horn to semisolid to liquid material. Developmental cysts are clinically relatively sharply defined, but often show connections to deeper-lying structures. Cystic tumors also contain cystic cavities, but primarily develop as solid tumors, such as cystic basal cell carcinomas or hidrocystomas. In this chapter the main cyst types are presented.