Sections of transurethral cystoscopic biopsy show a lesion with complex glandular structure arranged in papillary and cribriform architecture supported by a fine branching stromal stalk in some areas (Figs 01, 02 and 03). The lining cells are tall columnar epithelial cells with stratified or pseudostratified morphology (Figs 02 and 03). The cells display high degree of atypia with large nuclei and prominent nucleoli and pleomorphism ((Figs 02 and 03). These morphologic features are those of a prostatic duct adenocarcinoma.
Immunohistochemical stains show positive staining with prostate acid phosphatase (PAP) (Fig. 04) and prostatic specific antigen (PSA) (Fig 05), indicating that the tumor has a prostatic origin. Immunohistochemical stains for high molecular weight cytokeratin (CK903) are negative in the areas of tumor (Fig 06), thus confirming the absence of basal cells. The absence of basal cells establishes this as invasive carcinoma. This absence of basal cells is an important morphologic hallmark distinguishing it from cribriform high grade Prostatic Intra-epithelial Neoplasia (PIN). High grade PIN demonstrates presence of basal cells, and consequently positive staining with Cytokeratin 903.
Occasional single positive cells are seen at the periphery of the tumor (Figs 06 and 07).