Figure 2

Immunohistochemistry. (a) MUC1 in invasive micropapillary carcinoma demonstrates strong basal (stroma-facing, ‘reverse-apical’) reactivity. (b) MUC1 in typical invasive urothelial carcinoma with retraction also showed strong stroma-facing staining. (c) Although membranous reactivity for CA125 was more often seen in invasive micropapillary carcinoma, (d) typical invasive urothelial carcinoma with retraction also demonstrated staining with both strong intensity and extent. Uniform intense membrane staining of >30% of tumor cells (3+ score) with Her2Neu was seen in both (e) invasive micropapillary carcinoma and (f) typical invasive urothelial carcinoma with retraction. IMPC, invasive micropapillary carcinoma; IUC-R, invasive urothelial carcinoma with prominent retraction.