Diagnostic yield of touch imprint cytology of prostate core needle biopsies

Touch imprint cytology may provide additional information to core needle biopsy interpretation according to previous reports. The aim of this study was to investigate the diagnostic yield of this method in the diagnosis of prostate carcinoma. For this purpose, 452 transrectal prostate needle biopsies were evaluated from 56 patients. All patients were clinically suspicious of having prostate carcinoma. Two touch imprints were prepared from each fresh biopsy cylinder. Results of the standard histology and of the touch imprint evaluation were compared. Histologically negative biopsy cylinders were further evaluated for prostate carcinoma by fine step serial sectioning. The standard histological examination showed adenocarcinoma in 27 patients. Touch imprint cytology revealed atypical cells suspicious of carcinoma in 38 patients. This group included all 27 patients with positive standard histology and further 11 patients with initially negative core biopsy. Following serial sectioning, in three out of these 11 samples, histological evidence of a carcinoma could be proven. Fine step serial sectioning of all 29 core biopsies negative for carcinoma by standard histological examination, 26 patients remained negative. All three core biopsies initially negative by standard histology but positive after serial sectioning had cytology findings suspicious of carcinoma. We conclude, that in problematic cases the additional use of touch imprint cytology and serial sectioning of prostate core needle biopsies significantly improve the diagnostic accuracy.