This lesion would stain positive for which markers? A lesion staining positive for CD10 would most likely also stain positive for which marker?

• A. EMA
• B. CD3
• C. CK7
• D. P63

Answer: (A)

CD10-positive lesions often reflect epithelial differentiation, such as in renal cell carcinoma and related tumors. EMA is a broad epithelial marker that is commonly expressed in these same tumors. So when a lesion shows CD10 positivity, it is likely to also express EMA, signaling epithelial lineage. The other markers point to different lineages (CD3 is a T-cell marker), and while CK7 can be seen in some epithelial tumors, it isn’t as consistently associated with CD10-positive lesions; P63 marks basal or myoepithelial cells and is not typically linked with CD10-positive neoplasms. Therefore EMA is the best match.