Objective: To describe the cytopathological method used in the analysis of vitreous samples in the diagnosis of primary intraocular lymphoma (PIOL).
Participants: Seven patients with refractory posterior uveitis referred to a regional ocular inflammatory service were diagnosed as having PIOL between 1999 and 2006.
Methods: Clinical features of the uveitis and cytopathological preparation of the samples were described. All patients underwent vitrectomy and samples were placed in formal saline or prepared fresh. Following paraffin embedding generating a cell block, immunostaining, and polymerase chain reactions were performed.
Results: Five women (71.4%) and two men (28.6%) (mean age 67.7 years) were included. Five patients had diagnostic vitrectomy performed within 6 months of presentation, but in two patients diagnosis was delayed up to 2 years. Uveitis was bilateral in two patients. Cytologic and immunohistochemical staining prepared from the vitreous specimens showed PIOL in all patients, and PCR displayed single band of immunoglobulin heavy chain rearrangement in five out of six samples tested.
Conclusions: Diagnosis of PIOL is difficult due to small volume of sample with low number of malignant cells and inadequate preparation of samples. Our method of analysis with fresh samples together with immunohistochemistry and PCR analysis demonstrates a high yield of diagnosis reducing diagnostic delay.