Fig. 3

Histopathologic examination of the excised corneal button from the proband. a Hematoxylin and eosin staining of the tissue section revealed an irregular, layered structure of the corneal epithelium with variable thickness in which eosinophilic deposits (asterisks) were noted predominantly beneath the epithelium and involved the anterior stroma within a small range (see the arrow). Note the obliterated Bowman’s layer and distorted epithelium with varied thickness. b Orange-coloured congo-red-positive deposits of amyloid aggregates with variable size and irregular shape are found in subepithelia area, extending into the entire stroma (arrowhead). c Numerrous small single Periodic acid Schiff (PAS) stain-negative deposits were noted throughout the corneal stroma, which disturbed the normal architecture of the stroma. d The deposits did not stain red with Masson’s trichrome. Note the apparent subepithelial fibrosis. e UBM scan demonstrated markedly increased reflectivity, due to deposits within the lesions and irregular epithelial thickening induced by corneal opacities which project into anterior stroma. f OCT-scan also confirmed an extensive sawtooth-like pattern of hyperreflective material deposited along the Bowman layer