Reliability of vitreous histological detection of pathogenic fungi in the diagnosis of fungal endophthalmitis

Abstract

Purpose: To assess the value of histopathologic investigations of vitreous biopsy specimens in the diagnosis of fungal endophthalmitis compared with that of conventional smear and fungal culture. Methods: In this prospective study, 10 patients with clinically suspected fungal endophthalmitis of any etiology underwent intravitreal sampling and vitrectomy for diagnostic and therapeutic purposes. Infused vitreous biopsy samples were centrifuged and mixed with blood serum for hematoxylin and eosin and periodic-acid Schiff staining, whereas the remaining samples were submitted for smear and fungal culture. All slides were reviewed by an attending pathologist. Results: Vitreous specimens were obtained from 10 eyes of 10 patients. Positive histological diagnoses of fungal endophthalmitis from vitreous biopsies were made in seven cases (70%). The sensitivity of histological detection of fungi was higher than conventional smear (50%) or culture (40%); all these techniques are complementary. Conclusions: Specific histopathological detection of pathogenic fungi in clinical vitreous specimens could be helpful for the diagnosis of suspected fungal endophthalmitis. Positive histopathology results were seen in the majority of samples; however, difficulties in determining related fungal etiology limit its application.