Efficacy of restaining prostate needle biopsies with high-molecular weight cytokeratin

Prostate tissue and lesions obtained by needle biopsy may be scant and not survive cutting into the block; this study examined the efficacy of destaining hematoxylin and eosin-stained sections and restaining the slides using immunohistochemistry with high-molecular weight cytokeratin (high-molecular weight cytokeratin). We identified 105 prostate needle biopsies referred to Johns Hopkins Hospital in an 18-month period (January 1997-June 1998) that had been destained and restained for high molecular weight cytokeratin. The slides were reviewed for the Johns Hopkins Hospital diagnosis (benign, malignant, or equivocal), which had factored in the immunohistochemistry results, and for immunohistochemistry staining quality (optimal, suboptimal, stain failed, or lesion fell off). We obtained data on 96 cases from the referring institutions about the fixative and glass slides used for processing the needle biopsy. In 58% of cases, destaining and restaining with high-molecular weight cytokeratin allowed a definitive benign or malignant diagnosis to be made; in 79% of these cases, the staining was optimal. In only 13% of cases the diagnosis remained equivocal; of these, the stain worked optimally in only 36%. In 19% of cases, the stain failed. In 9% of cases, the lesion fell off; in all 7 cases with available data the tissue had been cut on non-charged slides. All but 3 cases were received in 10% neutral buffered formalin. There was no correlation between the use of charged (plus or lysine coated) or non-charged slides and the staining quality. Furthermore, in 12 instances, we received more than 1 specimen from the same referring institution, and in 6 of these instances there was variable staining in the different cases from the same institution. Destaining hematoxylin and eosin-stained slides and restaining for high-molecular weight cytokeratin is a useful technique that in the majority of cases enables a definitive diagnosis to be made. Tissue may survive the procedure better if originally cut on charged slides, but staining quality is no different for charged or non-charged slides.