[An abnormality often noted in pap smears. Koilocytotic atypia affects the squamous epithelium of the transformation zone. The cells involved show cytoplasmic vacuolization that might be related to their ability to store glycogen. The most characteristic feature of this condition is the peripheral cytoplasmic condensation associated with an increase of tonofilaments. (from Acta Cytol 1981;25:377-82 ) ( NCI )]