Background Triple antibody cocktail immunohistochemical staining is routinely used as an ancillary method to establish a diagnosis of prostate cancer in biopsies with small foci of atypical glands. Crush artefact can distort surgical margins in radical prostatectomy specimens, occasionally making it difficult to diagnose a positive margin.

Aim To investigate the ability of a cocktail stain to distinguish carcinoma from benign prostatic glands at the edge of crushed margins in prostatectomy specimens.

Methods 10 radical prostatectomy specimens with crushed benign glands at the surgical margins, and 20 with crushed margins positive for carcinoma were retrieved from the pathology archives. The latter included 16 (80%) with positive apical margins, 2 (10%) incised intraprostatic margins, and 1 (5%) soft tissue margin. Two-colour triple antibody stain using a cocktail of antibodies against α-methylacyl coenzyme A racemase (AMACR), high molecular weight keratin and p63 was performed on all the selected cases.

Results In 10/10 specimens with crushed benign glands, basal cell staining continued to be detectable, while AMACR staining was negative in all cases (0/10). In the positive margin cases, none of the crushed glands expressed basal cell marker staining (0/20), whereas 14/20 (70%) of the cases showed variable levels of AMACR positivity at the inked margin.

Conclusion Two-colour triple antibody cocktail stain is useful in the assessment of most, but not all, surgical margins with crushed artefact in prostatectomy specimens by helping to establish whether glands are malignant or benign.