Posterior polymorphous dystrophy--a histopathologic presentation.

The corneal button from a 34-year-old woman with posterior polymorphous dystrophy was studied by light and electron microscopy. Ultrastructural findings showed coexistence of epithelial-like cells and abnormal endothelial cells, and Descemet's membrane composed of a normal anterior banded layer, and an irregular posterior homogeneous and collagenous layer. We suggest that these abnormal endothelial cells are in the process of transforming into epithelial-like cells.