Defining Criteria for Diagnosis of Occult Lymphomatous Involvement in Cerebrospinal Fluid

Introduction: Currently, there is no consensus regarding diagnosis and treatment of occult lymphomatous menigeal involvement of cerebrospinal fluid (CSF) in patients with systemic non-Hodgkin lymphomas (NHL), especially in patients with minimal number of clonal cells detected by flow cytometry (FCM) or by cytology. Aim of the study: To describe a cohort of patients with occult lymphomatous involvement in cerebrospinal fluid including the diagnostic methods as well as management. Patients and methods: CSF at diagnosis of B-NHL was examined by FCM, cytology, biochemistry and microRNA analysis in a cohort of 62 patients (systemic DLBCL N=45, MCL N=15, Burkitt lymphoma N=2) between 2010 and 2013. Occult meningeal involvement was defined by: a/ FCM: absolute positive number of clonal cells Results and conclusions: According to described criteria we identified 8 patients with occult meningeal involvement at diagnosis (systemic DLBCL N=4, MCL N=3, Burkitt lymphoma N=1) out of 62 patients: 3 with negative FCM and positive cytology (2-14 cells/ul); and 5 with positive FCM These results suggest that examination of oncogenic microRNA in CSF at diagnosis is more sensitive method than FCM and cytology of CSF to detect the patients with occult CNS involvement and higher risk of CNS involvement and this should be reflected in treatment strategy in further clinical trials. Grants: GACR305 13-12449P, UNCE204021, PRVOUK: P24/LF1/3, P27/LF1/1, P 27/2012 LF3 Disclosures Spacek: Roche: Consultancy, Travel grants Other.