[973] Lymphoepithelioma-Like Carcinoma of the Urinary Bladder: Clinicopathologic, Immunohistochemical, and Molecular Features.

Sean R Williamson, Shaobo Zhang, Antonio Lopez-Beltran, Rajal B Shah, Rodolfo Montironi, Puay-Hoon Tan, Mingsheng Wang, Lee Ann Baldridge, Gregory T MacLennan, Liang Cheng. Indiana University, Indianapolis; Cordoba University, Spain; Caris Diagnostics, Irving, TX; Polytechnic University of the Marche Region, Ancona, Italy; Singapore General Hospital, Singapore; Case Western Reserve University, Cleveland

Background: Lymphoepithelioma-like carcinoma (LELC) in the urinary tract is a rare malignancy, named for its resemblance to nasopharyngeal undifferentiated carcinoma or lymphoepithelioma. Investigation of immunohistochemical and molecular characteristics of bladder LELC is limited. The pathogenesis and biological behavior of these tumors are controversial.
Design: We examined clinicopathologic features of urinary tract LELC, including light microscopy; immunohistochemistry (IHC) for CK7, CK20, 34ΒE12, p53, AMACR, TTF-1, EBV LMP-1 and CD30; in situ hybridization for HPV; and UroVysion fluorescence in situ hybridization (FISH).
Results: We identified tumors from 34 patients (M:F 2.8:1), ranging from 54 to 84 years of age (mean 70.2). Urothelial carcinoma in situ (CIS) was identified in 50% of patients. 34ΒE12 (75%) and CK7 (57%) were frequently positive in tumor cells, while TTF-1 and CD30 were consistently negative. Expression of p53 was noted in a subset of tumors (61%), while CK20 staining was negative with weak positivity in a single case. UroVysion FISH demonstrated frequent chromosomal abnormalities similar to those of urothelial carcinoma. In studied tumors with concurrent urothelial, squamous, sarcomatoid, and glandular components, identical FISH abnormalities were noted in both areas. In situ hybridization for HPV and immunostaining for EBV were negative in all studied lesions. All patients with pure or predominant LELC tumors treated with transurethral resection followed by chemotherapy were alive without evidence of disease at 2-5 years, while two patients treated in this manner with less than 50% LELC morphology had death from disease or distant metastasis.
Conclusions: Urinary tract LELC is a rare and interesting histologic variant of urothelial carcinoma. The frequent presence of UroVysion FISH abnormalities, urothelial CIS and p53 positivity by IHC in cases of urinary tract LELC suggest a similar pathogenesis to high-grade invasive urothelial carcinoma. In contrast to typical urothelial carcinoma, CK20 is frequently negative in LELC. Our findings support the hypothesis that pure or predominant LELC may be treated with transurethral resection and chemotherapy; however, a large-scale study with long-term followup is needed to better understand the biologic behavior of urinary bladder LELC.
Category: Genitourinary (including renal tumors)

Monday, February 28, 2011 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 122, Monday Morning


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