Renin-secreting tumors are classified into the following three groups: i) Tumors arising from the juxtaglomerular apparatus of the kidney; ii) renin-secreting renal tumors, including Wilms’ tumor, clear cell-type renal cell carcinoma, oncocytoma and mesoblastic nephroma; and iii) extrarenal tumors, including granulosa cell tumors, lung cancer and pancreatic cancer (8–11). Here, REN is linked to mesoblastic nephroma.