[Histopathology of corneal plaque in vernal keratoconjunctivitis]

The author reported 2 cases of vernal keratoconjunctivitis with corneal plaque showing a white board-like appearance. Conventional medications were not effective in both cases and during the course of the disease corneal ulcer developed followed by formation of corneal plaque. After the plaque spontaneously peeled off, or were surgically removed, the ulcers of both cases healed. The histological specimens from the 2 cases were examined by light and electron microscopy. The plaques showed lamellae-like structures, and formed alternate accumulation of hyaline-like material and another amorphous material. No cell components, such as corneal epithelial cells, keratocytes, or fibroblasts, were found either on the surface of and within the plaques. The corneal epithelial cells and/or eosinophils, however, were found at the edge of the plaque. These findings may suggest that these corneal plaques were formed by repeated episodes of deposition and that corneal epithelial cells and eosinophils may have been involved.