Extramedullary Hematopoiesis in Serous Cavity Fluids: A Closer Look at This Rare Phenomenon With Diagnostic Pitfalls and Prognostic Significance

This study uncovered methods to differentiate EMH from peripheral blood (PB) contamination in samples in the SF. PB contamination is an important differential for EMH, and cytomorphology remains a salient parameter for the diagnosis. The comparison of the number of red blood cells and white blood cells in the PB and SF helped to distinguish EMH from PB contamination when megakaryocytes were absent. The study showed that most patients died within a year of their EMH diagnosis in SF, suggesting a strong prognostic association of this finding with poor survival outcomes.