Touch imprint cytology of prostate core needle biopsy specimens: A useful method for immediate reporting of prostate cancer

Background: Cytology plays an important role in the preoperative assessment of many cancers. It is used as a first-line pathological investigation in both screening and diagnostic purposes. Aims: To determine the diagnostic value and accuracy of touch imprint cytology (TIC) smear of prostate core needle biopsy (CNB) specimens in the diagnosis of prostate carcinoma. Materials and Methods: One hundred and twenty-one patients had ultrasound-guided transrectal prostate CNB. A total of 1210 TIC smears were prepared from all CNB specimens. Results: Diagnoses of 1210 TIC smears were compared with the histopathological findings of the CNB specimens. One hundred and seventy (14) TIC smears were found positive for malignancy, 35 (2.9) were diagnosed as suspicious for malignancy and 1005 (83.1) were found negative for malignancy. Twenty-five of 35 suspicious imprints and 150 of 170 malignant smears were confirmed to be malignant on histopathological evaluation. Although 20 malignant TIC smears were defined as benign in standard histological preparations, 10 of them had definitive diagnosis of malignancy following extensive serial sectioning. Last of all, there were 10 false-positive cytology results. Moreover, 10 of the 35 suspected TIC smears were false negative when compared with the histopathological diagnosis. The sensitivity, specificity, positive predictive value and negative predictive value of touch imprint smear results were 100, 98, 90.2 and 100, respectively. Conclusions: TIC smears can provide an immediate and reliable cytological diagnosis of prostate carcinoma. It may clearly help the rapid detection of carcinoma, particularly in highly suspected cases that had negative routine biopsy results for malignancy with abnormal serum prostate specific antigen (PSA) levels and atypical digital rectal examination.