Prostatic Mucinous Adenocarcinoma
- Primary prostatic adenocarcinoma composed of at least 25% extracellular mucin
- Lakes of extracellular mucin must make up at least 25% of the volume of the tumor
- If less than 25%, designate as adenocarcinoma with focal mucin
- In a biopsy, designate as adenocarcinoma with mucinous features
- Epithelial component may
grow as strips, glands, cribriform structures and signet ring cells (rare)
- May float in mucin or line mucin filled spaces (usually partially)
- Collagenous micronodules (mucinous fibroplasia) may be present
- Grading has been somewhat controversial
- Some designate all as Gleason 4+4
- Some "mentally subtract the mucin" and score it as an ordinary carcinoma
- Usually results in score 4+3 (Osunkoya 2008)
- Clinical behavior appears to be similar to usual carcinoma (Osunkoya 2008, Lane 2006)
- PSA, PAP and low molecular weight cytokeratins positive
- High molecular weight cytokeratin negative
- CK7/20 double positive rare
- Urothelial and non-prostatic origin must be excluded
- Mucinous urothelial carcinoma
- HMWCK positive and CK7/20 double positive in most cases
- PSA and PAP negative (Osunkoya 2007)
- Some older reports find some positivity
- GI tract adenocarcinoma must be ruled out
- PSA and PAP negative
- CDX2 positive in GI primaries but also reported positive in 30% of mucinous prostate carcinomas (Leite 2008)
- History, endoscopy and imaging are critical
- Bibliography (for general references see Prostatic Acinar Adenocarcinoma)
- Humphrey, P. A. (2012), Histological variants of prostatic carcinoma and their significance. Histopathology, 60: 59–74.
- Osunkoya AO, Nielsen ME, Epstein JI. Prognosis of mucinous adenocarcinoma of the prostate treated by radical prostatectomy: a study of 47 cases. Am J Surg Pathol. 2008 Mar;32(3):468-72.
- Lane BR, Magi-Galluzzi C, Reuther AM, Levin HS, Zhou M, Klein EA. Mucinous adenocarcinoma of the prostate does not confer poor prognosis. Urology. 2006 Oct;68(4):825-30.
- Osunkoya AO, Epstein JI. Primary mucin-producing urothelial-type adenocarcinoma of prostate: report of 15 cases. Am J Surg Pathol. 2007 Sep;31(9):1323-9.
- Leite KR, Mitteldorf CA, Srougi M, Dall'oglio MF, Antunes AA, Pontes J Jr, Camara-Lopes LH. Cdx2, cytokeratin 20, thyroid transcription factor 1, and prostate-specific antigen expression in unusual subtypes of prostate cancer. Ann Diagn Pathol. 2008 Aug;12(4):260-6.
- For general diagnostic, grading and staging criteria, see also Prostatic Acinar Adenocarcinoma
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting/updates: 6/1/12
Prostatic Benign Lesions/Patterns Simulating Carcinoma