Pathologic observations made by retinal biopsy.

The authors report four cases in which retinal biopsy findings yielded unexpected or previously unreported diagnoses in patients with inflammatory retinitis. The tissue diagnoses included Wegener's retinal vasculitis in an immunosuppressed patient with a clinical diagnosis of cytomegalovirus retinitis, a novel viral form in the retina of a patient with cytomegalovirus retinitis, a case of acute retinal necrosis due to cytomegalovirus infection in an immunologically normal adult, and a case of ganciclovir-resistant herpes family viral retinitis. These cases illustrate the use of retinal biopsy in obtaining tissue for diagnosis and guiding treatment in selected cases of retinitis.