Emerging Concepts in Micropapillary Urothelial Carcinoma

Department of Anatomic Pathology, Cleveland Clinic, OH 44195, USA.
Advances in anatomic pathology (Impact Factor: 3.23). 05/2010; 17(3):182-6. DOI: 10.1097/PAP.0b013e3181d97851
Source: PubMed


Micropapillary urothelial carcinoma is a relatively uncommon variant of urothelial carcinoma, but its recognition carries important prognostic and treatment implications. Micropapillary morphology occurs in neoplasms arising in many different organ systems and displays aggressive biologic behavior regardless of its site of origin. On account of this association, micropapillary features in urothelial carcinoma should be reported regardless of whether the pattern is focal or dominant. The overall prognosis for micropapillary urothelial carcinoma is poor and recent studies suggest that early treatment with cystectomy could improve outcome, as these tumors are unlikely to respond to chemotherapy when used as a secondary treatment modality. This review discusses the histologic features required for diagnosis and the clinical significance of rendering a diagnosis of micropapillary urothelial carcinoma.

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    • "The recent rise in incidence appears to reflect the increased awareness of this entity, and the variable proportion occupied by this tumor is evidently due to a lack of established criteria for diagnosis and less-than-perfect interobserver reproducibility, both of which issue will be addressed later in this paper. This tumor predominantly affects male with male to female ratio of 5 : 1 to 10 : 1 which is higher than that for conventional UC which is 3 : 1 [1, 4–7]. "
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    ABSTRACT: Micropapillary carcinoma (MPC) of urinary tract is an uncommon variant of urothelial carcinoma with significant diagnostic and prognostic implications. Though MPC shows characteristic microscopic features, there exists interobserver variability and also it needs to be differentiated from the metastasis from other organs. The prognosis is generally poor, depending on the proportion of the micropapillary component in some reports. Early cystectomy in cases with only lamina propria invasion may be indicated according to recent studies. This review outlines the general features of this entity and briefly comments on the controversies and the recent development.
    Advances in Urology 10/2011; 2011:217153. DOI:10.1155/2011/217153
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    ABSTRACT: Invasive micropapillary carcinoma (IMPC) of the urinary tract is a well-described variant of the urothelial carcinoma with aggressive clinical behavior. Recent studies have proposed that patients with IMPC on transurethral resection should be treated with radical cystectomy regardless of the pathologic stage. Despite the potentially important therapeutic implications of this diagnosis, interobserver variation in the diagnosis of IMPC has not been studied. Sixty digital images, each from hematoxylin and eosin-stained slides, representing 30 invasive urothelial carcinomas (2 images per case), were distributed to 14 genitourinary subspecialists and each pathologist was requested to classify cases as IMPC or not. These cases included "classic" IMPC (n=10) and urothelial carcinoma with retraction and variably sized nests that might potentially be regarded as IMPC (n=20). The following 13 morphologic features were recorded as positive/negative for all cases independent of the reviewers' diagnoses: columnar cells, elongate nests or processes, extensive stromal retraction, lumen formation with internal epithelial tufting, epithelial ring forms, intracytoplasmic vacuolization, multiple nests within the same lacunar space, back-to-back lacunar spaces, epithelial nest anastomosis/confluence, marked nuclear pleomorphism, peripherally oriented nuclei, randomly distributed nuclei, and tumor nest size. In addition, a mean tumor nest size was calculated for each image based on the number of nuclei spanning the width of the nests. Interobserver reproducibility was assessed and the morphologic features were correlated with the classic IMPC and nonclassic/potential IMPC groups. In addition, the relationships between morphologic features, pathologists' interpretations, and case type (classic IMPC vs. nonclassic/potential IMPC) were evaluated using unsupervised hierarchical clustering analysis. Interobserver reproducibility for a diagnosis of IMPC in the 30 study cases was moderate (kappa: 0.54). Although classification as IMPC among the 10 "classic" IMPC cases was relatively uniform (93% agreement), the classification in the subset of 20 invasive urothelial carcinomas with extensive retraction and varying sized tumor nests was more variable. Multiple nests within the same lacunar space had the highest association with a diagnosis of classic IMPC. These findings suggest that more study of IMPC is needed to identify the individual pathologic features that might potentially correlate with an aggressive outcome and response to intravesical therapy.
    The American journal of surgical pathology 09/2010; 34(9):1367-76. DOI:10.1097/PAS.0b013e3181ec86b3 · 5.15 Impact Factor
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    ABSTRACT: 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. 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%). 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. 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.
    International Journal of Urology 01/2011; 18(1):49-54. DOI:10.1111/j.1442-2042.2010.02672.x · 2.41 Impact Factor
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