The term "renal ectopia" encompasses a wide variety of developmentally malpositioned kidneys. The kidneys originate in the fetal pelvis and rise to their normal position early in gestation. The most common type of malpositioning is a "pelvic kidney", in which a kidney fails to rise to its normal position.

Renal ectopia is associated with other abnormalities of development, but in itself is not pathologic. Depending of the nature of the malpositioning, the kidney may be at increased risk for

• obstruction (through compression of the upper collecting system by adjacent structures)
• reflux (abnormal relationship with the ureterovesicular junction (UVJ))

In this case, no ureteral stone, mass, or blood clot is present in the urinary system and the gross hematuria was considered to be due to some occult stress on the pelvic kidney.