Interobserver reproducibility in the diagnosis of invasive micropapillary carcinoma of the urinary tract among urologic pathologists.

Department of Pathology, Stanford University, Stanford, CA, USA.
The American journal of surgical pathology (Impact Factor: 4.59). 09/2010; 34(9):1367-76. DOI: 10.1097/PAS.0b013e3181ec86b3
Source: PubMed

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.

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    ABSTRACT: Micropapillary urothelial carcinoma (MPC) is a rare variant of urothelial carcinoma (UC) with an aggressive clinical course, an advanced stage at first presentation and a high metastatic potential. The aim or our study is to present five illustrative cases of MPC, diagnosed among the 21 patients with UC treated by radical cystectomy in the Department of Urology, County Hospital of Tirgu Mures, Romania, between January 1, 2011 and December 31, 2013. The morphological and immunohistochemical features of this rare and aggressive variant of UC, as well as a brief review of the literature are all presented. All five cases were associated with lymph node metastases with micropapillary features, regardless of the microscopic aspect of the tumor on the surgical specimens [transurethral resection (TUR) or cystectomy]. Three of them had a micropapillary component in the TUR, on the cystectomy specimen, or in both, along with lymph nodes metastases. In two cases, the MPC features were present only in the lymph node metastasis, with a conventional UC on the TUR and on the cystectomy. Immunohistochemical staining demonstrated that both micropapillary and associated conventional UC were positive for CK7 and CK20. Ki67 was expressed in 40% of tumor cells and CD34 was positive in the endothelial cells and negative in the flattened spindled cells lining the retraction spaces around tumor cell nests. MPC is a highly aggressive variant of UC with specific morphological characteristics. Any amount of micropapillary component found in UC is significant, and should be reported because it encompasses an aggressive clinical behavior and a poor prognosis.
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    European Urology 11/2014; 66(5):967–968. DOI:10.1016/j.eururo.2014.08.031 · 12.48 Impact Factor
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    ABSTRACT: Micropapillary carcinoma of the colon and rectum is associated with an adverse prognosis. This tumour type displays reverse polarity of the tumour cells and is stated to be characterised by an inside-out epithelial membrane antigen (EMA)/MUC1 staining. Nine cases of primary colorectal carcinoma and one omental metastasis were studied by means of immunohistochemistry, using antibodies to detect EMA, MUC1, MUC2, MUC3, MUC5AC, MUC6, CD10, CA125, carcinoembryonic antigen (CEA). The inside-out pattern staining with EMA/MUC1 ranged from diffuse circumferential through focal and partial to negative, but in some cases CEA, MUC3 and CD10 also showed this pattern staining, sometimes more clearly than did EMA or MUC1. The reverse polarity of colorectal micropapillary carcinomas is sometimes better visualised by immunostains other than EMA/MUC1.
    Pathology 08/2014; 46(6). DOI:10.1097/PAT.0000000000000144 · 2.62 Impact Factor


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