[Congenital megacalyces].

Congenital megacalyces is a calyceal anomaly characterized by nonobstructive dilatations of the calyces, associated with hypoplasia of the medullary pyramids. In the past three years, seven patients with congenital megacalyces were found incidentally during renal ultrasonic examination. There were five boys and two girls who were asymptomatic, except for a case with hematuria. Three cases presented bilateral and four unilateral, ages ranged from 7 to 14 years. In this series, all cases with dilatations of the calyces were initially detected by sonography, and then confirmed by other radiologic examinations. On intravenous urography, contrast material was visible at the normal time, but prolonged opacification. The radiological features presented widen calyces, flattened papillae, absence of papillary tips and usually no significant dilatation of the renal pelvis and ureter. The renal medulla had become thin. An ultrasound examination showed the kidneys with dilated calyces and decreased parenchyma. Renal pelvis and ureter were mostly normal in size. Diuretic radionuclide renogram T1/2 was performed in five cases, to disclose nonobstructive lesions. Radionuclide cystography, underwent in three cases, revealed no reflux phenomenon. Renal function was normal in all cases. Congenital megacalyces are a non-progressive lesions. Therefore, it is important to recognize the clinical entity and avoid unnecessary surgery. Since sonography is a noninvasive modality, it can serve as a tool for long-term follow-up of these patients and for the detection of possible future stone formation.