The Histopathology of Chronic "Radiation Conjunctivitis" Shows Diagnostic Features Similar to Those Seen in Radiation Dermatitis, Including Radiation Fibroblasts.

Abstract

Radiation therapy is a treatment modality for various ocular and ocular adnexal tumors. The histopathology of chronic radiation dermatitis has been well-described. The authors present two cases demonstrating and characterizing "chronic radiation conjunctivitis" which has not been histopathologically illustrated in detail. Retrospective case review of two patients who received proton beam irradiation for an anterior uveal melanoma and external beam radiation for conjunctival lymphoma, and developed leukoplakia and/or thickening of the eyelid margin and symblepharon. Hematoxylin and eosin-stained sections of eyelid margin and conjunctival biopsies as well as clinical histories were reviewed. Conjunctival biopsies in both cases revealed squamous epithelial metaplasia, chronic inflammation and bizarre-appearing stromal cells with hyperchromatic nuclei in a fibrotic/sclerotic stroma, consistent with chronic radiation conjunctivitis. These stromal cells are believed to be the same "radiation fibroblasts" described in chronic radiation dermatitis. The radiation fibroblast is characteristic for the diagnosis of chronic radiation conjunctivitis, as it is in radiation dermatitis. Features of squamous metaplasia of conjunctival epithelium, keratinization, subepithelial fibrosis/sclerosis and chronic inflammation are frequently found but not specific. A detailed history and other ancillary tests help differentiate cicatrizing conjunctival conditions, and biopsy should be performed in the setting of suspicion for a secondary malignancy.