Role of Immunohistochemical Markers in Differential Diagnosis of Prostatic Adenocarcinoma And Its Mimickers.

The Diagnosis Of Prostatic Adenocarcinoma Particularly When Present In Small Amounts, Is Often Challenging. Before Making A Diagnosis Of Carcinoma It Is Prudent For The Pathologist To Consider The Various Benign Entities That Can Mimic Prostatic Adenocarcinoma. A Valuable Method Of Classifying Benign Mimickers Is In Relationship To Major Growth Patterns Depicted In The Gleason Diagram. The Four Major Patterns Are Small Gland, Large Gland Fused Gland, And Solid. Most Of The Mimickers Fit In The Small Gland Type And Common Ones Giving Rise To False Positive Diagnosis Are Small Acinar Atrophy, Post Atrophic Hyperplasia, Atypical Adenomatous Hyperplasia And Seminal Vesicle. Other Normal Structures Like Cowper’s Gland Verumontanum Mucosal Glands, Paraganglionic Tissue And Mesonephric Glands Can Be Confused With Adenocarcinoma. Also Metaplastic And Hyperplastic Processes In The Prostate May Possibly Be Confused With Adenocarcinoma. Moreover, Inflammatory Processes Like Granulomatous Prostatitis, Xanthoma, And Malakoplakia May Replicate High-Grade Adenocarcinoma, Clear Cell Adernocarcinoma In Particular. Atypical Adenomatous Hyperplasia (Adenosis), A Alleged Precursor Of Adenocarcinoma Has Similar Features With Low Grade Adenocarcinoma And Might Cause Problems In Differential Diagnosis In Needle Biopsy Setting. At The Other End, Poorly Differentiated Adenocarcinoma Of The Prostate May Be Difficult To Distinguish From Inflammatory Infiltrates, Metastatic Carcinoma And TCC Involving The Prostate And Can Lead To False Negative Cancer Interpretation. The Pathologist’s Familiarity Of The Vast Collection Of Benign Mimickers Is Important In The Systematic Approach To The Diagnosis Of Prostatic Adenocarcinoma. Awareness Of These Patterns On Light Microscopy Coupled With The Cautious Use Of Immunohistochemistry Will Guide To A Correct Diagnosis And Avoid A False-Positive And False Negative Cancer Interpretation