Definition / General
- The 2 most frequent scenarios calling for the use of immunostains in prostate pathology are:
- The 3 way differential diagnosis between reactive / atrophic benign acini, atypical small acinar proliferation suspicious for but not diagnostic of cancer (ASAP), and invasive prostatic adenocarcinoma;
- Differential diagnosis between prostatic adenocarcinoma and urothelial carcinoma in transurethral resection material of the prostate or bladder neck, and rarely in biopsies
- The most important stains used to determine prostatic origin of tumor are PSA/prostate specific antigen and PAP/prostatic acid phosphatase
- The two main types of immunostains for workup of minute foci of carcinoma or suspicious for carcinoma are a basal cell immunostain cocktail (consisting of cytoplasmic marker cytokeratin 34βE12, also called cytokeratin 903, plus nuclear marker p63), and alpha-methylacyl CoA racemase (AMACR, P504S)
- These are often used together in a cocktail as a "triple stain"
- See related topics for their characteristics