UROLOGICAL SURVEY
Pathology
The plasmacytoid carcinoma of the bladder - rare variant of aggressive urothelial carcinoma
Keck B, Stoehr R, Wach S, Rogler A, Hofstaedter F, Lehmann J, Montironi R, Sibonye M, Fritsche HM, Lopez-Beltran A, Epstein JI, Wullich B, Hartmann A
Department of Urology, University Erlangen, Germany
Int J Cancer. 2010; 28. [Epub ahead of print]
The WHO classification of 2004 defines new histological and molecular variants of urothelial carcinoma. However there are limited data available on the clinico-pathological characteristics or prognosis of these variants. We present histopathological, molecular and clinical data of 32 plasmacytoid carcinomas of the bladder (PUC) showing that PUC is a high-grade tumor with molecular features of aggressive urothelial carcinoma, usually diagnosed in advanced pathological stage (64% pT3, 23% pT4) showing metastases in 60 % of the patients. Average survival of our cohort of PUC treated with radical cystectomy and adjuvant chemotherapy was lower than what is typically seen for comparable conventional urothelial carcinomas. 87% of the PUCs showed a negative or strongly reduced membranous staining of E-cadherin. Beta-catenin staining was negative in 22.5% and 16.7% of the remaining tumors showed nuclear accumulation. Aberrant CK20 expression (negative or > 10% of cells stained) and negative CK7 staining was found in 100% and 22.6%, respectively. 97% revealed positive staining for PAN-CK. CD138 was positive in 78 %, whereas MUM-1 expression was negative in all cases. Multi-target fluorescence in situ hybridization showed all PUCs to be highly aneuploid and polysomic. Deletions on chromosome 9p21 seem to play an important role in this variant. FGFR3 and PIK3CA mutation analyses yielded no mutations in any of the PUCs analyzed. TP53 mutation analysis showed mutations in 29%. In summary, PUC is a aggressive variant of bladder cancer with molecular features of advanced bladder cancer and evidence of WNT pathway activation in some of the cases.
Editorial Comment
The great majority of urinary bladder neoplasms derive from the urothelial (transitional) cells. Tumors originating from the mesenchimal cells are rare. The most common tumors are benign or malignant conventional urothelial neoplasms.
The World Health Organization has expanded the microscopic forms of urothelial carcinomas to include several unusual histological variants. The importance of the recognition of these unusual forms is related to: a) different prognosis; b) different therapeutic approach; and, c) the possibility of misinterpretation by the pathologist.
An important example is the small cell carcinoma with neuroendocrine differentiation. The importance of an accurate diagnosis of this variant of urothelial carcinoma is its response to newer chemotherapy protocols. The histological variants of urothelial carcinoma includes: nested variant, urothelial carcinoma with small tubules, microcystic urothelial carcinoma, micropapillary variant, lymphepithelioma-like, sarcomatoid carcinoma (carcinosarcoma), small cell carcinoma, plasmacytoid carcinoma, urothelial carcinoma with rhabdoid features, urothelial carcinoma with clear cytoplasm (glycogen-rich), urothelial carcinoma with trophoblastic differentiation, urothelial carcinoma with unusual stromal reactions, osteoclast-rich undifferentiated carcinoma, and giant cell carcinoma (1).
The study by Keck et al. based on a large series of plasmacytoid carcinoma showed that this tumor is an aggressive variant of bladder cancer with molecular features of advanced bladder cancer and evidence of WNT pathway activation in some of the cases.
Dr. Athanase Billis
Full-Professor of Pathology
State University of Campinas, Unicamp
Campinas, São Paulo, Brazil
E-mail: athanase@fcm.unicamp.br
- 1. Epstein JI, Reuter VE, Amin MB: Biopsy Interpretation of the Bladder, 2nd ed. Philadelphia, Lippincott Williams & Wilkins. 2010.
Publication Dates
-
Publication in this collection
23 Mar 2011 -
Date of issue
Dec 2010
