[824] Immunohistochemical (IHC) Profile To Distinguish Urothelial from Squamous Differentiation in Carcinomas of Urothelial Tract.

Christian Gulmann, Gladell P Paner, Rugvedita S Parakh, Donna E Hansel, Steven S Shen, Jae Y Ro, Chandrakanth Annaiah, Antonio Lopez-Beltran, Priya Rao, Komal Arora, Yong M Cho, Randa Alsabeh, Mahul B Amin. Beaumont Hospital, Dublin, Ireland; University of Chicago, IL; Cedars-Sinai Medical Center, Los Angeles, CA; Cleveland Clinic, OH; The Methodist Hospital, Houston, TX; Faculty of Medicine, Cordoba, Spain; MD Anderson Cancer Center, Houston, TX

Background: Urothelial neoplasms with squamous morphology raise the differential diagnosis between pure primary squamous cell carcinoma (SCC), urothelial carcinoma (UC) with squamous differentiation, and secondary involvement by SCC, e.g. from uterine cervix or anal canal. Accurate identification between these entities is critical due to differing prognosis and therapeutic strategies and the diagnostic dilemma may be compounded in limited samples.
Design: We evaluated the utility of an IHC panel of three urothelial-associated antibodies (Uroplakin III, S100P and GATA3) & two squamous-associated antibodies (CK14 and Desmoglein-3) in 50 primary urothelial neoplasms: 15 pure UC, 12 pure SCC and 23 UC with squamous differentiation. Squamous differentiation was defined by intercellular bridges or evidence of keratinization.
Results: Pure SCC were positive for CK 14 (100%) & Desmoglein-3 (75%), negative for GATA3 (0%) & Uroplakin III (0%); one case was S100P positive (9%). Pure UC had an opposite pattern & were positive for S100P (93%), GATA3 (93%) & Uroplakin III (73%) & were negative for Desmoglein-3 (0%); CK 14 was positive in 27% of cases. 74% of UC with squamous differentiation had expression of urothelial & squamous associated markers (S100P 83%, GATA3 35%, Uroplakin III 13%, CK14 87% and Desmoglein-3 70%); although reactivity for individual markers within some tumors did not always correspond with morphologic differentiation. Of the remaining 26%, 4 showed an overall 'squamous' immunoprofile whilst 2 cases showed a 'urothelial' immunoprofile.

 Pure SCC (n=12)Pure UC (n=15)UC with SCC diff (n=23)
Uroplakin III0%73%13%

Conclusions: 1) A panel of five antibodies reliably distinguishes carcinomas of the urothelial tract with squamous & urothelial differentiation suggesting potential utility due to management implications. 2) Immunostaining in tumors with both urothelial & squamous differentiation showed mixed profile. 3) Lack of correlation of some IHC markers with morphologic differentiation in a few tumors with mixed differentiation suggests that changes at the protein level precede phenotypic manifestation.
Category: Genitourinary (including renal tumors)

Tuesday, March 1, 2011 9:30 AM

Poster Session III # 179, Tuesday Morning


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