Case Studies Show Value of Flow Cytometry in MDS Diagnoses

Flow cytometry (FCM) analysis can be an important tool and provide diagnostic clarity in cases where patients with cytopenia are suspected of having myelodysplastic syndrome (MDS), according to a new case series published in the journal Cytometry Part B Clinical Cytometry.

Corresponding author Theresia M. Westers, PhD, of Amsterdam University Medical Centers in the Netherlands, and colleagues wrote that current guidelines already call for flow cytometric analysis in cytopenic patients suspected of having MDS, but they said most studies on the matter fail to elucidate how such testing can impact individual cases.

“Many reports on FCM in MDS focus on examples of aberrant immunophenotypic features without putting the results of a single patient in the context of clinical features and other diagnostic tools,” Westers and colleagues said.

In contrast, the investigators wanted to show how FCM can be meaningful in determining precise diagnoses for individual patients.

The 6 cases included in the report represented a variety of diagnostic issues and patient presentations. Two of the cases included patients whose diagnoses were confirmed based on FCM results that showed low cellularity and poor-quality bone marrow (BM) aspirates.

One of those cases was a 5-year-old boy, an unusual case in a disease category where most of the literature relates to older patients. The boy presented with fatigue, bruises, and a history of upper airway tract infections.

His doctors initially suspected a hypocellular MDS or anemia as the cause of his distress. After doing FCM, doctors refined their diagnosis to refractory cytopenia of childhood with aplastic anemia as a differential diagnosis.

“A [bone marrow] trephine examination showed a hypocellular, nearly aplastic marrow with reduced erythro- and myelopoiesis,” the authors reported. “Definite features of myelodysplasia were not seen, and the pathologist suspected aplastic anemia. Cytogenetics showed a normal karyotype (46,XY), molecular analyses were not performed.”

Doctors decided to take a second bone marrow sample about 4 weeks later. This time, histological, cytomorphological, and immunological analyses all suggested aplastic anemia and not dysplasia.

“The child was referred for allogeneic hematopoietic stem transplantation (allo-HSCT) and is doing well,” the investigators concluded.

In a separate case, a 33-year-old woman who was 30 weeks pregnant was examined for rapid onset anemia and nucleated red blood cells on her peripheral blood (PB) smear. A morphological assessment led investigators to suspected MDS, but they said her young age and the speed of onset made them question the diagnosis.

“Being pregnant, of young age, without excess of blasts, no defining cytogenetic abnormality and a rapid onset of cytopenia, additional diagnostic information from FCM analysis was instrumental to make this diagnosis,” the authors wrote. “The patient was monitored closely through the remaining period of her pregnancy but later progressed to acute myeloid leukemia.”

The investigators concluded that FCM can be a critical tool in the early phase of diagnostic investigation, but they added that the results of such an analysis need to be considered within the context of the broader picture of the patient’s case.

“In general, interpretation of FCM results should be made in the context of an integrated multimodal diagnostic approach—that is, discrepancies with results from other diagnostic tools should be investigated carefully,” they wrote.

Reference:

Westers TM, Saft L, van der Velden VHJ, et al. A series of case studies illustrating the role of flow cytometry in the diagnostic work-up of myelodysplastic syndromes. Cytometry B Clin Cytom. Published online February 18, 2022. doi:10.1002/cyto.b.22061