Multiparameter Flowcytometry for Diagnosis and Subtyping of Mature Lymphocytic Neoplasms in Peripheral Blood and Bone Marrow: A Prospective Observational Study

Abstract

Introduction: Multiparameter Flowcytometry (MFC) is a high throughput, quick, and practical technique for diagnoses of Chronic Lymphoproliferative Disorders (CLPDs). Indian CLPDs cases have distinct distribution and presentation than the developed world. Moreover, limited studies have confirmed the diagnostic utility of MFC in Indian CLPDs cases. Aim: To evaluate the diagnostic utility of MFC in peripheral blood and bone marrow aspirate of CLPDs cases. Materials and Methods: This was a single centre, prospective, observational study involving clinico-morphologically suspected or diagnosed 85 CLPDs cases. It was carried out in the Department of Pathology, Government Medical College and Hospital, Nagpur, Maharashtra, India, from January 2016 to November 2019. The patients were followed up for peripheral smear (PS) and Bone Marrow(BM) MFC and staging in nodal or extranodal Non-Hodgkin’s Lymphoma was done. Results: Clinico-morphological examination led to the diagnosis of 74 CLPD cases, while remaining 11 cases were strongly suspected. MFC immunophenotyping was contributory in diagnosing 74 CLPD cases which on further subtyping consisted of B-cell CLPD (N=70), and T-cell CLPD (N=3), while one case of B-NHL could not be subtyped. The most common B-cell CLPD included multiple myeloma (n=27), chronic lymphocytic leukemia (n=25), diffuse large B-cell lymphoma (n=7). T-cell CLPD included hepatosplenic gamma delta T-cell lymphoma (N=2) and adult T-cell lymphoma, follicular lymphoma (n=3), burkitt’s lymphoma (n=2), mantle cell lymphoma (n=2), prolymphocytic leukemia (n=2), splenic marginal zonal lymphoma (n=2), B Cell Non-Hodgkin’s Lymphoma (n=1). Finally, 11 suspected cases mostly comprised of reactive lymphocytosis (81.8%). Conclusion: MFC immunophenotyping led to diagnoses and determination of CLPD sub-class. It also resulted in rapid diagnoses of reactive hyperplasia and non-hematolymphoid malignancy which may mimic CLPD on morphology and hence, difficult to diagnose based on morphology alone.