Lipofuscinosis of the cornea. A clinicopathologic study of three cases
Background
Lipofuscin pigments are the indigestible residue of lysosomal activity usually associated with normal aging. Abnormal amounts of lipofuscin also are associated with certain disease processes. The rarity of lipofuscin in the cornea and the similarities between its staining properties and those of intracellular micro-organisms caused great diagnostic problems in three cases. The correct diagnosis of corneal lipofuscinosis was made after extensive histochemical, autofluorescent, and ultrastructural studies.
Methods
Clinical histories of three patients are correlated with morphologic and histochemical findings on five corneal buttons with lipofuscinosis.
Results
The histopathologic features of one cornea with chronic keratitis and three corneas from two patients with bilateral opacities of undetermined origin were mostly similar. Large amounts of lipofuscin pigment were found within macrophages and stromal keratocytes. Other pathologic findings were nonspecific, including phagocytosis of degenerated collagen fibrils, scarring, and neovascularization of the stroma.
Conclusion
The lipofuscin deposits are probably the consequence of a corneal degenerative process and not its cause, although their pathogenesis remains unclear. Familiarity with the morphologic appearance of corneal lipofuscinosis and its staining and autofluorescent properties is important because the small, 1- to 3-microns deposits may be mistaken for intracellular micro-organisms.
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