Resident Program - Case of the Month

Discussion

Prostate cancer is the second most common malignancy with an estimated 1.1 million new cases per year worldwide and is the fifth most common cause of death due to malignancy in men with an estimated 300,000 deaths per year.  Most cancers are detected in men over the age of 60 years old.  The incidence of prostate cancer rose from 1987 to 1992 in the USA which led to the adoption of serum PSA screening, which led to a decrease in mortality rates.  A known link to prostate cancer is lifestyle and dietary habits.  Glandular epithelial cells become injured by dietary carcinogens, estrogens, or oxidants which can cause chronic inflammation, leading to the potential for the development of cancer.  Prostate cancer is often clinically suspected in a patient with an elevated PSA or an abnormal digital rectal exam.

A subtype of prostatic adenocarcinoma that features large glands, lined by tall pseudostratified columnar cells is called ductal adenocarcinoma.  Ductal adenocarcinoma accounts for 3% of all prostate cancers, most of which are mixed tumors combined with acinar adenocarcinoma.  As in our case above, pure ductal adenocarcinoma is only found in 0.2-0.4% of prostate cancers.  Ductal adenocarcinoma that protrudes into the urethra may cause hematuria and obstructive symptoms. Periurethral cancers are often exophytic polypoid or papillary masses arising from the verumontanum.   Ductal adenocarcinoma most commonly grows along the prostatic ducts and usually also invades the prostatic stroma.  Metastasis is most common to the lymph nodes and bone.  Histologic features of ductal adenocarcinoma include amphophilic cytoplasm, round nuclei with prominent nucleoli and coarse chromatin, and mitotic figures.  Most ductal adenocarcinomas are more aggressive than the average acinar adenocarcinoma, with high stage, greater risk of recurrence after radical prostatectomy, and a higher mortality rate.  Papillary ductal adenocarcinoma should be assigned Gleason Pattern 4.  If there is comedonecrosis present, then a Gleason Pattern of 5 should be given. In contrast, a small subset of these tumors maintain periurethral gland involvement only and may be completely removed via transurethral resection.  Imaging studies and or biopsy evaluation of other regions of the gland can help distinguish between these two patterns of involvement.

 Immunohistochemistry tests for ductal adenocarcinoma show the following:

• Positive for PSA, PAP, and AMACR (in 77% of cases)
• Negative for p63 or HMCK when not an intraductal growth pattern

Works Cited

Amin, Ali, and Jonathan I. Epstein. “Pathologic Stage of Prostatic Ductal Adenocarcinoma at Radical Prostatectomy.” The American Journal of Surgical Pathology, vol. 35, no. 4, 2011, pp. 615–619., doi:10.1097/pas.0b013e31820eb25b.

Humphrey, Peter A., et al. WHO Classification of Tumours of the Urinary System and Male Genital Organs. International Agency for Research on Cancer, 2016.

Paner, Gladell. “Ductal Adenocarcinoma.” ExpertPath, app.expertpath.com/document/ductal-adenocarcinoma/f6151d4c-8363-48f7-b70a-8379a6dad0bf?searchTerm=Ductal%2BAdenocarcinoma.