Color Atlas of Hematology - Practical Microscopic and Clinical ...

Predominance of Mononuclear Round to Oval Cells63Predominance of Mononuclear Roundto Oval Cells (Table 5)The cell counts (per microliter) show a wide range of values and dependon a variety of conditions even in normal blood. Any disease may thereforeresult in higher (leukocytosis) or lower cell counts (leukopenia). Theassessment of cell counts requires the knowledge of normal values andtheir ranges (spreads) (Table 2, p. 12). The most important diagnostic indicatortherefore is not the cell count but the cell type. In a first assessment,mononuclear (round to oval) and polynuclear (segmented) cells arecompared. This is the first step in the differential diagnosis of the multifacetedspectrum of blood cells.Absolute or relative predominance of mononuclear cells points to a definedset of diagnostic probabilities. The differential diagnostic notes oppositecan help with a first orientation.Consequently, the most important step is to distinguish between lymphaticcells and myeloid blasts. The nuclear morphology makes it possibleto distinguish between the two cell types. In lymphatic cells the nucleususually displays dense coarse chromatin with slate-like architecture andlighter zones between very dense ones. In contrast, the immature cells inmyeloid leukemias contain nuclei with a more delicate reticular, sometimessand-like chromatin structure with a finer, more irregular pattern.