Hypoplastic Right Kidney

• Incomplete development resulting in a smaller (<50%) kidney with fewer calyces and papillae (usually < 5) but normal function

• Not to be confused with dysplasia, which results from collecting system obstruction and creates a bizarre appearance of the kidney. Hypoplastic kidneys are smooth with short infundibulae and sometimes have clubbed calyces

• Segmental hypoplasia (Ask-Upmark kidney): usually upper pole with deep transverse groove. Associated with severe hypertension. Etiology is controversial (congenital vs. sequelae of pyelonephritis)