Fig. 4From: Tumor-to-tumor spread: a case report and literature review of renal cell carcinoma metastasis into thyroid cancerH&E stain section (upper panel of image, 100 × total magnification) showing juxtaposition of clear cell RCC (left) and FVPTC (right). Immunohistochemical stain for PAX8 (lower left panel) shows expected positivity in both the RCC and the papillary thyroid carcinoma, while immunostain for TTF-1 (lower right panel) shows differential expression with positivity in the papillary thyroid carcinoma and negativity in the RCCBack to article page