Primary gelatinous drop-like corneal dystrophy in a white woman. A pathologic, ultrastructural, and immunohistochemical study.

A white female with primary gelatinous drop-like corneal dystrophy (PGDD) was followed from the ages of 8 to 37 years. During this time, she underwent repeated lamellar and penetrating keratoplasties on both sides due to relapsing bilateral corneal opacifications. The diagnosis of PGDD was based on the histology of the corneal specimens obtained at 10 and 36 years of age, as well as on the characteristic clinical appearance and course. Electron microscopy showed typical amyloid fibrils. Immunohistochemical staining was mildly positive for amyloid AL (light chain), but negative for amyloid AA, AF, AB, and keratin. Thus, the precursor protein of the amyloid deposits in PGDD might derive from immunoglobulins, e.g., from the tear film. However, the precursor protein might derive from a different origin altogether. In that case, the positive staining for amyloid AL would translate nonspecific absorption of fragments of light chains.