A new form of cellular arrangement in guinea-pig ear epidermis.

A new type of squame arrangements is described in guinea-pig ear epidermis. It is characterized by overlapping obliquely-angled outer cells and squames, which thus form a roof-tile pattern. This pattern develops in epidermis that is thicker than about 42 micron; in thinner epidermis the outer cells and squames form the usual columnar stacks. It is concluded that the roof-tile pattern, which is usually directed towards the ear edge, is typical of slight to moderate hyperplasia. In extreme hyperplasia, when the strata granulosum and corneum are destroyed, only cellular disorder is seen.