Fig. 1

(a) Papillary adenoma is characterized by an encapsulated papillary proliferation arising in the renal cortex (original magnification × 50). (b) Papillary RCC, type 1 is characterized by papillary cores covered by a single layer of tumor cells and circumscribed by a fibrous capsule (original magnification × 50). (c) Clear cell RCC with alveolar nests of tumor cells and microscopic cysts (original magnification × 100). (d) Clear cell RCC with blood-filled microscopic cysts metastatic to adrenal gland (original magnification × 100)