Cell block cytology - Improved preparation and its efficacy in diagnostic cytology

Cell blocks prepared from residual tissue fluids and fine-needle aspiration s can be useful adjuncts to smears for establishing a more definitive cytop athologic diagnosis. They can be particularly useful for categorization of tumors that otherwise may not be possible from smears themselves. A modifie d cell block technique using an improvised ethanol formalin fixative (Natha n alcohol formalin substitute)followed by a simple paraffin processing sche dule is described. This improved preparation offers excellent cytomorpholog ic features corresponding closely to cells in Papanicolaou-stained smears a nd ensures optimal preservation of histochemical and immunocytochemical pro perties. The technique is simple and reproducible and uses routine safe lab oratory chemicals. The efficacy of cell blocks also is discussed.