Optimized preembedding method improves the histologic yield of prostatic core needle biopsies

BACKGROUND. The aim of this study was to optimize the core share of prostat ic core needle biopsies using a novel preembedding method, and to investiga te the influence of the number of cores per tissue block on the histologic yield per section level. METHODS. Twenty-four core needle biopsies were taken from a fresh prostatec tomy specimen, using an Ib-gauge needle. Twelve core needle biopsies were c onventionally fixed floating free in formalin-filled containers, whereas 12 biopsies were stretched between two nylon meshes, and placed in tissue cas settes before fixation. The total number of tissue sections per paraffin bl ock necessary for complete workup of the tissue was determined. Using image analysis, the relation of the area of every fifth section level was calcul ated in relation to the total projected area of the biopsies. Both methods of tissue processing were compared for both parameters. RESULTS. In contrast to the curved biopsies after conventional processing t he optimized preembedding method generally led to stretched cores after fix ation and embedding;. This method led to a 100% decrease in total number of tissue sections necessary for complete workup and to higher percentages of the tissue amount per section level compared to the total projected core a rea. These parameters were also influenced by the number of cores per paraf fin block, but to a minor degree. CONCLUSIONS. This study shows that optimized preembedding of prostatic need le biopsies improves the histologic yield per section level. The continuous occurrence of representative sections could improve diagnostic accuracy in the histological examination of prostatic core needle biopsies. (C) 2000 W iley-Liss, Inc.