[901] E-Cadherin Expression in Plasmacytoid, Signet Ring Cell and Micropapillary Variants of Urothelial Carcinoma: Comparison with Usual Type High Grade Urothelial Carcinoma

MG Lim, NV Adsay, DJ Grignon, AO Osunkoya. Emory University School of Medicine, Atlanta, GA; Indiana University School of Medicine, Indianapolis, IN

Background: Loss of E-cadherin expression has been linked to the invasive phenotypes of a variety of neoplasms, including lobular breast cancer. The expression of E-cadherin in variants of urothelial carcinoma (UCa) relative to usual type UCa, maximum depth of invasion and angiolymphatic invasion has not been well characterized.
Design: 8 cases of micropapillary UCa, 4 cases of plasmacytoid UCa, 2 cases of UCa with signet ring cell features and 2 cases of UCa with mixed plasmacytoid and signet ring cell features, all obtained from cystectomy/cystoprostatectomy cases were identified. 9 cases of usual type invasive and non-invasive high grade UCa were also included in the study. Immunohistochemical stains for E-cadherin was performed on all cases. Pathologic parameters including depth of invasion and presence of angiolymphatic invasion were documented.
Results: Maximum depth of invasion: Micropapillary UCa: extravesicular extension 3 of 8 cases; muscularis propria invasion 4 of 8 cases; lamina propria invasion 1 of 8 cases. Plasmacytoid UCa: extravesicular extension 2 of 4 cases; muscularis propria invasion and lamina propria invasion 1 of 4 cases each. UCa with signet ring cell features: extravesicular extension and muscularis propria invasion 1 of 2 cases each. UCa with mixed plasmacytoid and signet ring cell features: muscularis propria invasion and lamina propria invasion 1 of 2 cases each. Usual type high grade UCa: extravesicular extension 6 of 9 cases; non-invasive 3 of 9 cases. Angiolymphatic invasion: Micropapillary UCa 8 of 8 cases; plasmacytoid UCa 2 of 4 cases; UCa with signet ring cell features 1 of 2 cases; UCa with mixed plasmacytoid and signet ring cell features 1 of 2 cases. Usual type high grade UCa 6 of 9 cases. E-cadherin expression: All 8 cases of micropapillary UCa were positive for E-cadherin in the micropapillary component and adjacent usual type UCa. The 4 cases of plasmacytoid UCa, 2 cases of UCa with signet ring cell features and 2 cases of UCa with mixed plasmacytoid and signet ring cell features were all negative for E-cadherin. All 9 additional cases of usual type high grade UCa were diffusely positive for E-cadherin.
Conclusions: E-cadherin is diffusely positive in usual type UCa and micropapillary UCa irrespective of pathologic stage and angiolymphatic invasion. Loss of E-cadherin expression may be a marker of plasmacytoid and signet ring cell differentiation in UCa.
Category: Genitourinary (including renal tumors)

Monday, March 22, 2010 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 129, Monday Morning

 

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