Fascin as an identifier of metastatic urothelial carcinoma: A retrospective study of fine-needle aspiration cell blocks and histologic tissue microarrays.

Fascin, a marker of invasiveness in urothelial carcinoma, has not been correlated with metastatic disease. To enhance diagnostic accuracy and correctly identify primary site for appropriate patient management, fascin may be a useful marker in metastatic urothelial carcinoma. In this study, we evaluated twenty five cases with adequate cell block material for immunohistochemistry (IHC) staining in patients with either concurrent or previously resected urothelial carcinoma between 2005 and 2010. Fascin, thrombomodulin, uroplakin, cytokeratin 7, and cytokeratin 20 IHC were performed on paraffin-embedded cell block serial sections. Fascin was over-expressed in the majority (23/25, 92%) of metastatic urothelial carcinomas. We found concordant results in 22 of 25 (88%) cases for fascin and thrombomodulin IHC staining. Either fascin and/or thrombomodulin demonstrated positive staining in 25 of 25 (100%) cases. Histologic tissue microarrays of 72 genitourinary (GU) carcinomas of the kidney and prostate were stained with fascin to reveal all cases to be negative in the cells of interest. In comparing fascin with the traditional markers of urothelial carcinoma, fascin expression is of greater frequency and intensity than thrombomodulin. The combination of fascin and/or thrombomodulin identified all 25 (100%) cases of urothelial carcinoma. Fascin IHC staining is equivalent in frequency and intensity to cytokeratin 7. Fascin is an advantageous diagnostic complement, to thrombomodulin and/or cytokeratin 7, in the setting of metastatic urothelial carcinoma, and is highly specific and sensitive relative to GU malignancies.