RESUMO
Anterior corneal dystrophies involving Bowman's membrane and anterior stroma include several subtypes of uncertain etiology: the Reis-Bückler, Thiel-Behnke, Grayson-Wilbrandt, and "honeycomb" dystrophies. The clinical and pathologic features of these dystrophies overlap to such a degree that they may represent variations of the same entity. Typically, they all present symptoms beginning in childhood, have a dominant pattern of heredity, and manifest painful, recurrent corneal erosions. Some cases have also been interpreted as representing macular and granular dystrophy. In the present report, we describe a pedigree of affected patients whose corneal dystrophy shared many of the clinical and pathologic features of the Reis-Bücklers and allied subtypes but which differ from all in causing visual symptoms late in life and with minimal signs of recurrent erosion. Histopathology revealed a thickening of the anterior stroma by the addition of a partially disorganized and degenerating tissue in which collagen Type III (fetal or repair collagen) is intermixed with the normal (mature) Type I collagen in the entire stroma. This is accompanied by irregular swelling of the basal epithelial cells and hyperplasia of the basement membrane (collagen Type IV, laminin and fibronectin), suggesting an aberrant influence of the epithelium on collagen synthesis.
