Utility of p63 and Alpha Methyl Acyl CoA Racemase in the Lesions of Prostatic Mimickers: An Observational Study

Introduction: Prostate adenocarcinoma is the most commonly occurring cancer in men. Differentiation of prostatic adenocarcinoma from prostatic mimickers is sometimes difficult on the sole basis of histologic findings. Diagnosis of carcinoma is based on Immunohistochemistry (IHC) by negative immune reaction with p63 and positive staining with Alpha Methyl Acyl CoA Racemase (AMACR).

Aim: To evaluate the utility of p63 and AMACR in the prostatic mimickers.

Materials and Methods: In this analytical observational study, all prospective prostatic mimickers with Transrectal Ultrasound (TRUS) guided biopsies received in the Pathology Department of Bharati Vidyapeeth Medical College, Pune, India in a tertiary care hospital from July 2020 to July 2022 were studied. 70 cases were collected, studied and analysed which included 38 Transurethral Resection of the Prostate (TURP) specimens and 32 TRUS guided tissue biopsies. The Haematoxylin and Eosin (H&E) stained slides of all the cases were examined and divided into three categories-malignant (08 cases), prostatic mimickers (53 cases) and suspicious for malignancy (09 cases). Further, these cases were subjected to IHC for p63 and AMACR. Statistical Package for Social Sciences (SPSS) version 25.0 software was used for data analysis using Chi-square test along with p-value.

Results: Out of the 53 cases of prostatic mimickers and nine cases suspicious for malignancy, 56 were positive for p63 and six were negative for p63. There was a statistically significant association between p63 IHC staining and the differentiation of benign cases from malignant prostatic lesions (p<0.001). The sensitivity and specificity of p63 were 93.3% and 100%, respectively. There were eight cases of prostate adenocarcinoma stained with AMACR, all were positive. The sensitivity and specificity being 100%. Results revealed that there was a significant statistical association between the positive IHC staining of AMACR and prostatic adenocarcinoma (p<0.001).

Conclusion: The diagnostic performance of p63 and AMACR proves to be significant in differentiating between the mimickers of prostatic lesions and adenocarcinoma. IHC is recommended to reduce diagnostic error in suspected cases.