The radiological diagnosis of congenital multicystic kidney ‘radiological triad’

Abstract

Congenital multicystic kidney is the most common cause of an abdominal mass in infancy, and it may persist into adult life and be incidentally discovered. The pre-operative diagnosis is usually not made because the diagnostic features, consisting of a unilateral non-functioning kidney with or without a palpable flank mass, are shared by other more serious renal diseases. As a result, these patients generally have been subjected to surgical exploration to confirm the clinical suspicion of congenital multicystic kidney in order to make sure that one is not dealing with the more serious or malignant renal diseases. Accurate radiological diagnosis of congenital multicystic kidney, however, is entirely possible, provided the intravenous urogram, retrograde pyelogram, and abdominal aortogram are employed in combination. These diagnostic procedures not only make the primary diagnosis of congenital multicystic kidney, but also reveal the nature of the underlying congenital anomaly of the contralateral urinary tract that is reported to be present in approximately 30% of these patients. In this presentation emphasis, is strongly made on the radiological recognition and awareness of the nature and significance of this innocent renal lesion, which when left alone is not known to be harmful to the body. The pathognomonic radiological triad of congenital multicystic kidney consists of: 1. Unilateral non-functioning kidney on the excretory urogram with a flank mass or shell-like calcification on the plain film. 2. Absent or atretic proximal ureter on the retrograde pyelogram. 3. Absent or hypoplastic renal artery, no collateral arterial supply and no nephrogram on the abdominal aortogram.