Detection of Central Nervous System Infiltration by Myeloid and Lymphoid Hematologic Neoplasms Using Flow Cytometry Analysis: Diagnostic Accuracy Study.

INTRODUCTION: Infiltration of the central nervous system (CNS) by hematologic or lymphoid malignant cells can cause extensive neurological damage, be progressive and fatal. However, usually, the cerebrospinal fluid (CSF) has low cellularity and rapid cell degeneration, which can impair cytometry analysis. Storage and transport measures, sample preparation, and staining protocols can interfere with diagnostic accuracy. OBJECTIVE: To calculate the diagnostic performance of flow cytometry (FC) using a cell stabilizer for sample preservation compared to cytomorphology in the detection of CNS infiltration by lymphoid and hematologic neoplasms. METHODS: Cell samples from all consecutive patients with suspected infiltration by hematological malignancies evaluated between January 2014 and December 2016 were included. Cases were analyzed by FC using a cell preservation medium and cytomorphology. Sensitivity and specificity were calculated. RESULTS: From 414 CSF samples, 72 had a phenotype compatible with characteristics of infiltration by hematological disease, whereas cytology was positive for 35 cases. FC showed higher sensitivity and specificity when compared to cytomorphology, particularly in cases with cellularity under 5 leukocytes/mm3. CONCLUSION: We demonstrated that collecting CSF in a medium that preserves the stability of the sample improves accuracy when compared to cytomorphology, particularly in low-volume and low-cellularity samples.

A importância da citometria de fluxo no diagnóstico raro de mieloma mielomonocítico / The importance of flow cytometry in the rare diagnosis of myelomonocytic myeloma

O mieloma múltiplo consiste na proliferação de células plasmáticas. Raramente apresenta, ao diagnóstico, morfologia de células imaturas com citoplasma amplo basofílico, sugerindo quadro leucêmico inicial. O objetivo deste artigo é mostrar a importância da imunofenotipagem na elucidação destes achados, morfológicos, pela expressão simultânea de antígenos plasmocíticos, mielomonocíticos e de linhagem linfóide T, confirmando a hipótese diagnóstica de mieloma mielomonocítico. Apresentamos dois casos de mieloma mielomonocítico através de análise morfológica (coloração pancromática de Romanovsky), citoquímica (PAS, peroxidase, sudan black, alfanaftil acetato esterase e oil red), citogenética e imunofenotipagem por citometria de fluxo em sangue periférico e medula óssea, de acordo com as técnicas recomendadas. Foram utilizados os anticorpos monoclonais: CD2, CD3, CD4, CD5, CD7, CD10, CD13, CD15, CD19, CD20, CD25, CD33, CD34, CD38, CD45, CD56, CD71, HLAðDR, TCR alfa/beta, TCR gama/delta, kappa, lambda, IgM e IgD de superfície e intracitoplasmática, assim com MPO, CD79a e CD3 intracitoplasmático. Utilizamos as técnicas de banda G e FISH nas análises citogenéticas. Foram observadas alterações clonais em ambos os casos, sendo uma com trissomia do cromossomo 8 e outro caso com deleção do braço longo do cromossomo 7 e do braço curto do cromossomos 6. Os percentuais de positivadade encontrados nos anticorpos monoclonais CD4, CD7, CD10, CD13, CD14, CD15, CD33, CD38 E CD56 de forte expressão, HLAðDR, TCR gama/delta, MPO e IgM intracitoplasmático no histograma de volume x complexidade e no histograma de CD45 x complexidade permitiram concluir este diagnóstico em ambos os casos, demonstrando a importância do método