[823] Selective Immunohistochemical Markers To Distinguish between Metastatic High Grade Urothelial Carcinoma to the Lung and Primary Poorly Differentiated Invasive Squamous Carcinoma.

Aaron M Gruver, Danielle Westfall, Carol F Farver, Daniel J Luthringer, Adeboye O Osunkoya, Jesse K McKenney, Mahul B Amin, Donna E Hansel. Cleveland Clinic, OH; Cedars-Sinai Medical Center, Beverly Hills, CA; Emory University School of Medicine, Atlanta, GA; Stanford University School of Medicine, CA

Background: The distinction between primary lung carcinomas and lung metastases from other sites, especially the urinary tract, is a common diagnostic dilemma in surgical pathology. As urothelial carcinomas (UCCs) can demonstrate a broad range of morphology, and frequently demonstrate squamous differentiation, the distinction between metastatic UCC to the lung and primary pulmonary invasive squamous cell carcinoma (SCC) can often be challenging. Individual immunohistochemical (IHC) markers are often not especially helpful in these situations, as both p63 and high molecular weight cytokeratin, which are often used in the diagnosis of UCC, are expressed in SCCs from various anatomic locations.
Design: We examined a panel of 12 established and emerging IHC markers in 30 patients with paired urinary tract and presumed metastatic lung tumors to establish a useful diagnostic panel.
Results: The best markers to aid in the distinction between poorly differentiated metastatic UCC and primary pulmonary SCC were CK7, CK20, GATA-3, S100-A1 and UROIII, with the utility of the latter dependent upon the quantity of tissue available for analysis. The observed percent positive staining in non-metastatic UCC and primary pulmonary SCC with these markers was CK7 (100% vs. 33%), CK20 (54% vs. 7%), GATA-3 (78% vs. 23%), S100-A1 (0% vs. 20%) and UROIII (14% vs. 0%) respectively.
Conclusions: When interpreted in close correlation with clinical history and routine H&E histomorphology, these markers (CK7, CK20, GATA-3, S100-A1 and UROIII) may be a useful adjunct in the distinction of metastatic high grade UCC to the lung.
Category: Genitourinary (including renal tumors)

Tuesday, March 1, 2011 9:30 AM

Poster Session III # 180, Tuesday Morning

 

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