Diagnosis of intraocular lymphoma by polymerase chain reaction

Cytopathological examinations have been used in the diagnosis of intraocular lymphoma. However, sometimes it is not easy to detect malignant cells in the biopsy specimens. We applied a method that identified monoclonal proliferation of B lymphocytes by using polymerase chain reaction (PCR) in the diagnosis of patients suspected to have intraocular B-cell lymphoma. Three specimens of the diagnostic vitrectomy were studied by cytological examination and by PCR to amplify the complementary determining region (CDR3) of immunoglobulin heavy chain (IgH) gene. As a positive control, a biopsy specimen of an orbital lymphoma was examined; four vitrectomy specimens from patients with diabetic retinopathy, proliferative vitreo-retinopathy, acute retinal necrosis (ARN) and macular hole were negative controls. On cytologic examination, no malignant cells were found in three specimens: suspected intraocular lymphoma and one ARN. In contrast, a discrete band that reflected monoclonal proliferation of B lymphocytes was detected by PCR in specimens from two patients and the positive control. Vitrectomy specimens from the negative controls, including ARN, did not show a discrete band on PCR. Two cases of ocular malignant lymphoma were diagnosed by PCR identification of monoclonal proliferation of B lymphocytes. This method may be an additional diagnostic tool in the diagnosis of intraocular B-cell lymphoma.