Mucin-producing urothelial-type adenocarcinoma of prostate: report of two cases of a rare and diagnostically challenging entity

Abstract

The differential diagnosis of mucin-producing adenocarcinoma of the prostate includes conventional prostatic adenocarcinoma with mucin production, secondary adenocarcinoma usually of colorectal origin and, very rarely, urothelial-type adenocarcinoma arising from either the prostatic urethra or proximal ducts. Conventional prostatic adenocarcinoma with mucin production is readily identified by routine microscopy and immunohistochemistry. The distinction between secondary adenocarcinoma and urothelial-type adenocarcinoma, however, can present a significant diagnostic challenge. In addition, documented examples of the latter in the prostate are exceptionally rare. A transurethral resection of prostate specimen and prostatic needle biopsies from two patients showing urothelial-type adenocarcinoma of the prostate were identified in our consultation files. One of the patients subsequently underwent a radical prostatectomy. Both patients had negative gastrointestinal endoscopic workups. Transurethral resection of prostate material from two patients with clinically confirmed secondary adenocarcinoma of colonic origin involving the prostate and a prostatectomy specimen with mucinous conventional prostatic adenocarcinoma were also identified for comparison purposes. Formalin-fixed, paraffin-embedded sections were stained for prostate-specific antigen (PSA), prostatic acid phosphatase, carcinoembryonic antigen, cytokeratin 7, cytokeratin 20 and high molecular weight cytokeratin 34bE12. The urothelial-type adenocarcinoma cases were diffusely positive for cytokeratin 7 and focally positive for 34bE12 and cytokeratin 20, consistent with an origin from the urothelium of the prostatic urethra or proximal prostatic ducts. In contrast, the secondary adenocarcinoma of colonic origin cases were diffusely cytokeratin 20 positive and either negative or focally positive for cytokeratin 7 and negative for 34bE12. The mucinous conventional prostatic adenocarcinoma was positive for PSA and prostatic acid phosphatase and negative for cytokeratin 7, cytokeratin 20 and 34bE12. All tumors were positive for carcinoembryonic antigen. Modern Pathology (2005) 18, 585-590. doi:10.1038/modpathol.3800317Keywords: urothelial carcinoma; mucinous adenocarcinoma; urethra; prostate; immunohistochemistry Carcinoma arising in the male urethra, with or without involvement of the prostate, is uncommon and usually occurs during the sixth and seventh decades, with 95% of cases occurring after the age of 45 years. 1 Obstructive symptoms due to a urethral mass or stricture are the usual presenting features. 2,3 Chronic irritation, infection, and trauma, including that from instrumentation used to relieve strictures, are the major predisposing factors. 1,2 In one series, 37% of patients had a history of venereal disease, 35% had stricture, and 7% had suffered trauma. 3 It has been reported that up to 88% of patients with urethral carcinoma have a history of urethral stricture. The most common site for stricture, the bulbomembranous urethra, is also the most comm...

Prognosis of Mucinous Adenocarcinoma of the Prostate Treated by Radical Prostatectomy

“…4,5,7,9,10,16,[19][20][21][22][23][24][25]27,28,30,31,35 Mimics of mucinous adenocarcinoma of the prostate include secondary involvement of the prostate by mucinous adenocarcinoma of the colon, and mucinous adenocarcinoma of the bladder or urethra. 6,15,24,33,37,38 The infiltrating component of these nonprostatic mucinous cancers contains lakes of mucin lined by tall columnar mucinous epithelium showing varying degrees of nuclear atypia. In contrast mucinous adenocarcinoma of the prostate contains single round and cribriform glands with relatively bland cytology floating within the mucinous lakes.…”

Urothelial-Type adenocarcinoma of the prostate mimicking metastatic colorectal adenocarcinoma

“…One previously reported patient died of disease with liver metastasis within one year of initial diagnosis (2). Another patient experienced local recurrence 4 years status-post simple prostatectomy (1).…”

“…Curtis et al (2) proposed that a panel of antibodies to PSA, PSAP, CK7, CK20 and HMWK would be useful in differentiating urothelial-type adenocarcinoma, metastatic colorectal adenocarcinoma, and conventional prostatic acinar adenocarcinoma. Urothelial-type adenocarcinomas should be positive for HMWK and CK7 and may be positive for CK20, but should not express PSA and PSAP.…”

“…Curtis et al (2) described 2 additional cases in which both were centered around the prostatic urethra but were not associated with urethritis glandularis. The authors discussed the utility of immunohistochemistry in distinguishing these tumors from other histologic mimickers including conventional prostatic adenocarcinoma and metastatic colorectal adenocarcinoma (2).…”

A Case of Advanced Mucinous Adenocarcinoma of Bladder in an Adult Patient Treated With Capecitabine-Based Chemotherapy and Review of Literature

“…A negative result for K903 and P63 is suggestive for a derivation from normal urothelium. 17 CK7 and CK20 staining profiles have been used to distinguish tumors from different sites. Gastrointestinal tumors, including colorectal cancers, tend to be CK20þ and CK7À; for urothelial neoplasms, the staining is the exact opposite; PBA usually shows mixed staining pattern CK20þ and CK7þ.…”