Histopathology of recurrent gelatinous drop-like corneal dystrophy

To elucidate more fully the histopathology of gelatinous drop-like corneal dystrophy in a case that recurred and was operated on 7 years after the original surgery.

Transmission electron microscopy, including the use of cuprolinic blue to image sulfated proteoglycans, and horseradish peroxidase as a marker for in vitro epithelial permeability.

Our patient's epithelium was often abnormally thick, and many intercellular spaces were present at all levels, although cell-cell contact via desmosomes was also evident. Horseradish peroxidase, when used as an in vitro tracer, was able to penetrate the most superficial tight junctions of the corneal epithelium. Basal epithelial cells were not columnar, and numerous spike-like projections protruded into the underlying amyloid/collagenous tissue from the basal epithelium. Beneath this, duplication of a discontinuous epithelial basement membrane was noted. In this region, collagen often coexisted with amyloid, the deposition of which was extensive. As in some other corneal pathologies, long-spacing collagen was detected. The association of small proteoglycans with collagen was unremarkable, although some abnormally large, sulfated proteoglycan filaments were interspersed with the amyloid and underlying stroma.

Recurrent gelatinous drop-like corneal dystrophy shares several histopathologic features with its primary counterpart, although some features, such as the presence of abnormally large, sulfated proteoglycans and long-spacing collagen, the permeability of the epithelial tight junctions, and the duplication of the epithelial basement membrane, have not been reported previously.