Spleen alterations in hairy cell leukemia: a scanning electron microscopic study.

In Hairy Cell Leukemia (HCL) peripheral blood and bone marrow cells show under the scanning electron microscope (SEM) a characteristic surface with numerous ruffles and microvilli. The spleen of a patient affected by HCL was studied by SEM after fresh sectioning and routine preparation. Cells with the typical "hairy" surface were observed infiltrating the red pulp, altering the normal reticular meshwork and causing red blood cell distortion. In the sinuses, hairy cells adhered to the endothelial cells causing sinus dilatation and destruction. Aggregates of hairy cells delimiting pooled erythrocytes were also observed and may represent the "pseudosinuses" described in previous light and transmission electron microscopic studies. These preliminary findings may explain the condition of hypersplenism which characterizes HCL. In addition, SEM is proposed as a rapid and simple method to identify HCL spleen involvement.