The Usefulness of Diagnostic Vitrectomy in Neoplastic and Non-Neoplastic Masquerade Syndrome: An Observational Study

Introduction: Masquerade intraocular inflammation may be considered neoplastic or non- neoplastic masquerades such as primary intraocular lymphoma, leukemia, infectious and inflammatory diseases. These pathologies require a definitive diagnosis, as the treatment modalities are different. The aim of our study was to investigate the safety and usefulness of diagnostic vitrectomy with vitreous humor flow cytometry in eyes with intraocular inflammation of unknown etiology. Methods: A retrospective observational study included 35 eyes of 29 patients with atypical intraocular inflammation unresponsive to corticosteroid therapy. In all cases diagnostic vitrectomy with flow cytometry analysis of the vitreous specimen was performed. Results: Among 35 eyes, the result of diagnostic vitrectomy analysis showed unspecific inflammatory response in 7 (20.0%) eyes, confirmed neoplastic diseases in 5 (14.3%) eyes. All of them it was intraocular lymphoma but one of the eyes with primarily diagnosed lymphoma and one of the eyes with primarily diagnosed unspecific inflammatory response in flow cytometry has been diagnosed finally as a choroidal melanoma after enucleation of the eyeball. Diagnostic vitrectomy excluded neoplastic disease in 7 eyes (20.0%). In 3 eyes (8.6%) bacterial infection, in 4 eyes (11.4%) viral infection. In 2 eyes (5.7%) we excluded bacterial infection, in 7 cases (20.0%) no conclusive results were obtained. The most common adverse event was cataract in patients (12 eyes, 34.3%). Conclusion: Diagnostic vitrectomy with flow cytometry of vitreous humor is helpful in confirming the clinical suspected diagnosis of posterior segment inflammation. Flow cytometry need to be complemented with other diagnostic test including cytopathology, especially in cases suspected of intraocular lymphoma. Flow cytometry of the vitreous humor in choroidal melanoma is not a useful diagnostic tool.