Potential diagnostic pitfalls caused by blood film artifacts in prolymphocytic leukaemia. Observations in two cases.

The diagnosis of lymphoproliferative disorders is based on a combined evaluation of the clinical, immunological and morphological findings. Cytological details may vary with the quality of the smear. We report two cases of prolymphocytic leukaemia in which cytoplasmic hairs or protrusions were observed when the films were not dried quickly. In one case the artifacts led to an initial erroneous interpretation of hairy cell leukaemia 'variant'. The cytoplasmic outline was smooth in both cases when the smears were immediately fan-dried. The findings underscore the necessity of high standards of excellence, even for the simple technique of blood film preparation, in order to avoid undesirable artifacts which may result in diagnostic misinterpretation.