The value of touch imprint cytology of prostate core needle biopsy specimens – Kuwait experience
Objectives: Touch imprint cytology (TIC) is a reliable, cost-effective technique for the diagnosis of cancer. The aim of this study was to determine the diagnostic value and accuracy of TIC of prostate core needle biopsy (CNB) specimens in predicting the final histology in patients with suspected prostate cancer.
Subjects and methods: TIC was carried out on 354 core needle biopsy specimens taken from 59 patients with suspected prostate cancer as indicated by a high prostate serum antigen (PSA) level or abnormal findings on rectal examination. All biopsies were taken under transrectal ultrasound (TRUS) guidance. Two touch imprints were prepared from each CNB. The TIC results were correlated with CNB.
Results: TIC revealed evaluable results in 336/354 (94.9%) CNB specimens analyzed, with the following cytological diagnosis: malignancy in 40 (11.9%), atypical features in 47 (14%) and benign results in 249 (74.1%) specimens. Histopathological examination of the 40 CNB specimens showing malignant features on TIC confirmed the diagnosis of prostate cancer. In 24/47 (51.1%) cases with atypical cytology, histopathological assessment of the CNB specimens revealed benign features in 7 and prostatitis in 17, while high-grade prostatic intraepithelial neoplasia (HGPIN) and carcinoma were seen in 3 and 20 specimens, respectively. In 12/249 (4.8%) cases showing benign results on TIC, histopathological examination of the CNB specimens revealed an abnormal histology in the form of HGPIN in 9 (75%) and carcinoma in 3 (25%) cases. TIC accurately predicted the final histology in 336 cases with a sensitivity of 84% and a specificity of 90.8%. When excluding atypical cytology on TIC and HGPIN on CNB, the sensitivity and specificity were 93% and 100%, respectively. A strong correlation was seen between TIC and CNB (p < 0.001).
Conclusions: The routine use of TIC complements CNB reports and helps to provide an immediate and reliable cytological diagnosis of prostate lesions. TIC and serial sectioning of CNB specimens significantly improve the diagnostic accuracy.