renal segmental hypoplasia renal segmental hypoplasia renal segmental hypoplasia is a kidney with a partially developed or atrophic renal cortex. renal segmental hypoplasiaother namesask-upmark kidneyspecialtynephrology presentation ask-upmark kidneys are a cause of secondary hypertension that can be curable. cause it is thought to be congenital or the consequence of vesicoureteral reflux. in ivu “slit scar” is seen. diagnosis