Keratitis caused by an unusual fungus, Phoma species

Abstract

Purpose: To describe the histopathologic profile of a case of keratitis caused by Phoma species and to evaluate the role of polymerase chain reaction in the diagnosis of this unusual fungal infection.

Methods: Clinical information was extracted after a review of the medical records of a 72-year-old man developing a nonhealing corneal ulcer with brownish pigmentation. Microbiologic cultures and histopathologic examination were performed on the keratectomy specimen. Polymerase chain reaction was performed on DNA extracted from five (10-microm thick) paraffin-embedded sections using panfungal primers.

Results: Histopathologic examination revealed round spherules of variable diameter (5-30 microm) admixed with septate hyphae at the edges of the perforated cornea. Microbiologic cultures grew a fungus identified as Phoma species. Polymerase chain reaction from the specimen yielded a single product with an approximate size of 360 bp.

Conclusion: Phoma species, though rarely pathogenic to humans, may cause keratitis in some patients. To our knowledge, this is the first well-documented case of Phoma keratitis.