[1033] Histopathological Tumor Features Associated with Her2 Amplified Urothelial Bladder Cancers

Joelle Tschui, Diana Rotzer, Roland Seiler, Achim Fleischmann. Institute of Pathology, University of Berne, Berne, Switzerland; University Hospital of Berne, Berne, Switzerland

Background: Approximately 10% of invasive urothelial bladder cancers (UBC) are Her2 amplified. Anti-Her2 targeted therapies might become an option for these UBC, however, little is known about their morphological features.
Design: A cohort of 150 patients with UBC was evaluated by fluorescence in situ hybridization (FISH) for Her2 amplification. The histopathological features of the 13 amplified primary tumors (8.6%) were compared with 13 matched non-amplified primary tumors.
Results: Urothelial carcinomas with Her2 amplification presented with a broader variety of histomorphological subtypes than the control group, showing particularly a high frequency of micropapillary tumor components (10/13 patients). In contrast, the Her2 non-amplified tumors mainly presented the classical solid type of urothelial carcinoma and apart from two cases with sarcomatoid growth patterns, did not show a particular trend towards growth of any morphological subtype. In addition, Her2 amplified carcinomas demonstrated a high degree of intratumoral chronic inflammation while peritumoral inflammation was low.
Conclusions: UBC with Her2-amplification are morphologically heterogeneous, frequently demonstrate micropapillary growth and show strong intratumoral and week peritumoral chronic inflammation. These features may help pathologists to identify UBC harboring Her2 amplification.
Category: Genitourinary (including renal tumors)

Wednesday, March 21, 2012 1:00 PM

Poster Session VI # 138, Wednesday Afternoon


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