Histopathological Study of Prostate Core Needle Biopsies in Enugu, Southeast Nigeria and the Role of Immunohistochemistry in Resolving Diagnostic Dilemmas.

BACKGROUND: Prostate lesions constitute a major cause of morbidity and mortality in Nigerian adult males. Prostate cancer (Pca) is now being reported as the second most frequently diagnosed malignancy in adult males. On some occasions, histopathological results may be inconclusive with the tissue sample tagged 'suspicious' of prostate cancer. Immunohistochemistry using Alpha methyl acyl CoA racemase (AMACR) and High molecular weight cytokeratin (HMWCK) can be used to clarify such cases. The study aims to evaluate the role of immunohistochemistry in resolving diagnostic dilemmas following core needle prostate biopsy. METHODOLOGY: This was a retrospective study performed between January 2013 and December 2017. The Hematoxylin and Eosin (H&E) stained slides and their corresponding archived formalin-fixed paraffin tissue blocks of cases over the study period were retrieved and reviewed. The suspicious cases were subjected to immunohistochemistry using AMACR and HMWCK to determine their actual status. RESULTS: A total of 1838 prostate biopsy cases were received over the five-year period. A mean age of 69±9 years was observed, while the most common Gleason score was 6 [International Society of Urological Pathology (ISUP) grade group 1]. Among the 1838 prostate biopsy cases retrieved, 147 cases were excluded because of incomplete data. Hence, 1691 core needle prostate biopsies were used for the study. The highest number of core needle prostate biopsy cases were benign (57.8%), followed by malignant lesions (39%), whereas 3.4% were suspicious. Among the cases with suspicious status, 67.2% were AMACR marker positive and HMWCK marker negative, while 32.8% were AMACR marker negative and HMWCK marker positive. Therefore, 67.2% of the suspicious cases were resolved to be malignant and 32.8% were resolved to be benign. CONCLUSION: Immunohistochemistry is very useful in resolving cases of suspicious prostate lesions. The required staining apparatus should be made readily available in our tertiary centers.