Fig. 2

Histopathological examination of renal angiomyoadenomatous tumor (RAT): gross image demonstrating multiple interconnecting cystic spaces with intervening thickened areas with patchy hemorrhagic areas (a). Hematoxylin and eosin (H&E) stained lower magnification image showing cystic spaces (epithelial component) along with thick-walled blood vessels (blue arrow) in renal parenchyma (b, h&e, × 40). Epithelial component arranged in adenomatous/glandular/tubular pattern with basally located bland small beaded nuclei and intimately surrounded by thin vascular channels. The cytoplasm of the cells is optically clear with blisters like apical snouts giving the appearance of “Shark’s Smile/moth-eaten” (green arrow). Stromal smooth muscle component (red arrow) (H&E; × 100, c; and × 400, d). The epithelial component is immunopositive for pan-cytokeratin (e, × 400), immunonegative for CD10 (f, × 400), and immunonegative for HMB-45 (g, × 40). The stromal smooth muscle was immunopositive for smooth muscle actin (SMA) (h, × 100)