Cytological diagnosis of vitreoretinal lymphomas: A case series

Objective To assess the cytological diagnosis and follow-up of patients suffering from vitreoretinal lymphoma (VRL) diagnosed in our institution. Methods and Results From January 2010 to June 2017, we collected 15 patients with VRL. Twelve patients had diffuse large B-cell lymphoma (DLBCL); of these, 11 had primary central nervous system (CNS) DLBCL, one had ocular localisation of follicular lymphoma, one had extranodal NK/T-cell nasal type lymphoma and one had chronic lymphocytic leukaemia. The results of the cytological examination (cell morphology and immunocytochemistry) of the vitreous fluid were available for 9/15 VRL. The interleukin-10/-6 ratio was >1 in eight of 12 DLBCL. Molecular testing was useful in 6/15 cases (clonality evaluation or MYD88 L265P mutation testing). Eight out of 11 primary CNS DLBCL patients had CNS involvement, with 22-month progression-free survival. In our series, only two out of 11 CNS DLBCL patients died of disease after 2 and 5 years, respectively. Conclusions The short delay to assert the diagnosis of VRL could explain the quite good prognosis in our series, which highlights the need to consider a diagnosis of DLBCL as first step. The cytological features, as a reliable way to identify VRL, must always guide the choice of techniques for further investigations given the small amount of vitreous fluid available for analysis.