PROSTATIC ADENOCARCINOMA WITH PLEOMORPHIC AND DUCTAL FEATURES, GLEASON SCORE 4+5=9, INVOLVING 12 OF 12 (12/12) CORES AND APPROXIMATELY 80% OF THE SAMPLED TISSUE.
Ductal prostatic adenocarcinomas are most commonly located centrally, producing exophytic urethral lesions. These patients most commonly present with urinary obstruction and hematuria, and the central location makes it difficult to detect on digital rectal exam. Serum Prostate Specific Antigen (PSA) levels have been noted to increase in patients with ductal disease, but less so than in patients with purely acinar disease. Additionally, the clinical stage at diagnosis is often more advanced in these patients, and identifying ductal-type cancer is an independent predictor of disease specific mortality. Ductal carcinoma has been noted to metastasize to the liver, lungs, penis, and testis, which are unusual sites of metastasis for acinar prostatic carcinoma.
Ductal prostatic adenocarcinoma is found in up to 5% of prostate cancer diagnoses, often as a minor component of acinar adenocarcinomas. Cytological atypia varies from minimal to marked, and multiple architectural patterns may be present. Papillary architecture is most common, but cribiforming also occurs. Stromal desmoplastic reaction occurs more frequently with ductal-type carcinomas than with acinar-type, and is often with hemosiderin deposition. Most ductal adenocarcinomas are equivalent to Gleason pattern 4, but are classified as Gleason pattern 5 if comedo-necrosis is present.
Immunostains can be useful to diagnose prostatic ductal adenocarcinoma, but there are few differentiators between acinar and prostatic subtypes. Ductal adenocarcinoma expresses PSA and prostatic-specific acid phosphatase (PSAP) and Ki67 levels tend to be elevated, which may be helpful when working up metastases. Racemase is also expressed, but often at lower levels than in acinar-type carcinoma. Differentiating high grade PIN (Prostatic Intraepithelial Neoplasia) from ductal prostatic adenocarcinoma can be difficult, but comedonecrosis and fibrovascular cores are more common in ductal-type cancers. Basal cell markers (such as p63 and CK903) can be helpful if they are negative, as this excludes an intraepithelial process.
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Contributed by Ryan A. Collins, MD and Anil V. Parwani, MD, PhD