[1586] Use of S100P, IMP3 and pVHL Immunopanel To Aid in the Interpretation of Bile Duct Biopsies with Atypical Histology or Suspicious for Malignancy.

Michael T Schmidt, Fai Chung, Fan Lin, Haodong Xu, Hanlin L Wang. Cedars-Sinai Medical Center, Los Angeles, CA; Geisinger Medical Center, Danville, PA; University of Rochester, NY

Background: Histological evaluation of small bile duct biopsies is a known challenge. Our prior studies have shown that S100P, the insulin-like growth factor 2 mRNA binding protein 3 (IMP3) and the von Hippel-Lindau gene product (pVHL) are a useful immunopanel for the distinction between adenocarcinoma and benign biliary epithelium (Levy et al. Hum Pathol 41:1210-9, 2010). The current study aimed to determine if this panel could be useful in making a more confident diagnosis for challenging bile duct biopsies with atypical histology or suspicious for malignancy.
Design: A total of 14 histologically challenging bile duct biopsies were immunohistochemically stained for S100P, IMP3 and pVHL. Nuclear staining for S100P, cytoplasmic staining for IMP3 and membranous staining for pVHL were considered positive. The staining intensity for pVHL was also evaluated to determine if it was reduced in the cells of interest in comparison with histologically unremarkable biliary epithelium present in the same biopsies. Clinical, surgical, radiologic and pathologic follow up data were obtained for all 14 cases.
Results: Follow up data showed 9 cases to be adenocarcinomas and 5 cases to be benign. In the malignant group, the following staining patterns in atypical or suspicious cells in the initial bile duct biopsies were observed: S100P-positive/IMP3-positive/pVHL-negative or reduced (n=5), S100P-positive/IMP3-negative/pVHL-negative or reduced (n=3), and S100P-positive/IMP3-positive/pVHL-positive (n=1). In the benign group, 2 biopsies showed a S100P-positive/IMP3-negative/pVHL-positive pattern. In the remaining 3 biopsies that showed a S100P-positive/IMP3-positive/pVHL-negative or reduced pattern, the atypical cells were histologically dysplastic.
Conclusions: Bile duct adenocarcinoma frequently shows positive IMP3 staining and negative or reduced pVHL staining. This staining pattern can also be seen in dysplastic epithelium in the absence of invasive carcinoma. When IMP3 is negative, positive S100P with reciprocal loss or reduction of pVHL staining is also indicative of malignancy. On the contrary, benign biliary epithelium typically lacks IMP3 staining and retains normal pVHL expression. These results indicate that an immunopanel consisting of S100P, IMP3 and pVHL can be helpful in aiding in the interpretation of bile duct biopsies with atypical histology or suspicious for malignancy.
Category: Liver & Pancreas

Wednesday, March 2, 2011 9:30 AM

Poster Session V # 200, Wednesday Morning

 

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