Can p63 Alone Resolve the Mystery of Suspicious Lesions in Prostate Biopsies?- A Study of Interobserver Agreement

Abstract

Introduction: Prostatic biopsies more often, present diagnostic dilemma raising the suspicion of malignancy. Small acinar pattern, limited atypical glands and benign mimickers are few pitfalls. Markers like p63, High Molecular Weight Cytokeratin (HMWCK) detect presence/absence of basal cells and p504s, malignant epithelial cells. This study highlights the usefulness of p63 alone in the resolution of suspicious foci. Aim: To ascertain the effectiveness of p63 in resolving doubtful prostatic biopsies. Materials and Methods: Cross-sectional study on 30 prostatic biopsies with suspicious foci from January 2014 to July 2016. Immunohistochemistry with p63, HMWCK and p504s was performed on all the biopsies and final diagnosis was arrived at. The routine paraffin sections and p63 slides were reviewed by two independent pathologists who were blinded to the above diagnosis. Their opinion was analysed against the final diagnosis with SPSS v.23 to calculate sensitivity, specificity and interobserver agreement. Results: The diagnosis achieved by performing three markers were benign in 24 and adenocarcinoma in six cases. Pathologist 1 concurred in 30 (100%) cases and pathologist 2 in 29 (97%). A p63 had (6/6) 100% sensitivity and specificity in diagnosing adenocarcinoma with pathologist 1. With pathologist 2, it had sensitivity of (6/6) 100% and specificity of (23/24) 95.83%. Cohen’s kappa was 0.902 which showed significant agreement. Conclusion: A p63 alone can help the pathologist to arrive at a diagnosis and is highly sensitive and specific. Interobserver agreement is also significant indicating high reproducibility.

Keywords

• ambiguous lesions
• immunohistochemistry
• prostatic carcinoma