Objectives: To stratify patients with micropapillary urothelial carcinoma of the urinary bladder based on the percentage of micropapillary component and to correlate tumor volume with other clinicopathological features.
Methods: Cases of micropapillary urothelial carcinoma of the urinary bladder from 2002 to 2009 were identified. Only patients with available follow-up information were included in the analysis. Tumor volumes were stratified based on the percentage of micropapillary component (<50%, >50% and 100%).
Results: Overall, 24 cases were analyzed. Mean patient age was 71 years (range 55-86 years), with a male to female ratio of 3:1. Six cases (6/24; 25%) were composed entirely of micropapillary component. A total of 12 cases (12/24; 50%) showed >50% micropapillary component. Six cases (6/24; 25%) showed <50% micropapillary component. A higher percentage of micropapillary urothelial carcinoma component was significantly associated with male sex, regional lymph node metastasis and pathological stage (P-values = 0.0005, 0.01 and 0.03, respectively). The percentage of the micropapillary component was, however, unrelated to patients' survival.
Conclusions: The present study confirms that micropapillary urothelial bladder carcinoma is typically aggressive and presents with advanced stage disease in most cases. A quantification of the micropapillary component is to be recommended. An accurate diagnosis of this entity in relatively small biopsies or transurethral resection of bladder tumor specimens is especially critical to define the best treatment plan.
© 2010 The Japanese Urological Association.