Abstract
Purpose: :
Ten myxomas of the cornea have been reported in the literature; however the histopathological features, particularly the immunohistochemical characteristics, have not been studied extensively. We reviewed eight cases from our ophthalmic pathology laboratory in an effort to establish characteristic histopathological features.
Methods: :
Light and electron microscopic examination were performed on all cases. Hematoxylin and eosin, PAS, alcian blue, and colloidal iron stains were used. The immunohistochemical markers studied included vimentin, smooth muscle actin, muscle-specific actin, S-100, glial fibrillary acidic protein, neuron specific enolase, lysozyme, alpha-antitrypsin, CD34, CD68, and epithelial markers AE1/AE3, CK903, and CK8.18.
Results: :
Seven of the eight cases had a history of accidental or iatrogenic trauma. The other myxoma occurred in a patient with keratoconus. Two of our cases were correctly diagnosed clinically as corneal myxoma on the basis of an opaque, gelatinous appearance that also had been noted in some of our prior cases by the same cornea specialist (GM).Histopathologically, all of the myxomas were subepithelial and showed varying degrees of disruption and degeneration of Bowman’s layer. Characteristic stellate and spindle cells in a loose mucopolysaccharide-rich matrix were uniformly present on light microscopic examination. Electron microscopic examination additionally revealed characteristic nuclear invaginations. Vimentin and smooth muscle actin stains were positive in the spindle and stellate cells in all cases. Muscle-specific actin was positive in 4 of 8 cases. CD34 was positive in the keratocytes of the adjacent normal stroma but not within the myxoma in all cases.
Conclusions: :
Our results support the theory of reactive myofibroblastic proliferation as the origin of corneal myxoma in most cases, rather than a primary neoplastic process.
Keywords: pathology: human • cornea: clinical science • immunohistochemistry