Abstract
Renal ectopia and fusion anomalies are Congenital Anomalies of the Kidney and the Urinary Tract (CAKUT) that are usually incidentally detected and asymptomatic. Patients affected present a higher risk of complications like recurrent urinary tract infections or obstruction. Pancake kidney (PK) is one of the rarest types of renal anomaly with complete fusion of the superior, mild and inferior poles of both kidneys in the pelvic cavity. Each kidney has its own excretory system with two ureters that do not cross the midline. In the asymptomatic cases, a conservative approach should be performed. Surgical management may be needed when urological problems occur. PK is often associated with congenital anomalies of other organs. Ultrasound is the first line radiological examination for the diagnosis and the follow-up of kidney malformations. The main sonographic findings suggesting PK diagnosis are a large and lobulated renal mass consisting of two fused lateral lobes without an intervening septum located in the pelvic cavity. Each lobe usually has a separate pelvicalyceal system, the renal pelvis is anteriorly placed and the ureters are usually short and enter the bladder normally without crosses the midline. Ultrasonography gives useful information on the morphology and volume of the organ, and on its vascularization through the use of the Color- and Power-Doppler. Computer Tomography and Magnetic Resonance Urography are second level techniques used to confirm the diagnosis and to evaluate the presence of other abnormalities. The knowledge of the imaging findings and the anatomy of congenital renal malformations is important to avoid diagnostic pitfalls and misinterpretations. We report the case of a 14-years old female with PK who was misdiagnosed with a horseshoe kidney (HSK) during an abdominal ultrasound.
SOMMARIO
L’ectopia e le anomalie di fusione renale rientrano nel gruppo delle Anomalie Congenite del Rene e del Tratto Urinario (CAKUT, Congenital Anomalies of the Kidney and Urinary Tract). Generalmente asintomatiche, queste condizioni vengono descritte come reperti incidentali. I pazienti affetti presentano un rischio più elevato di complicanze dell’apparato urinario, come infezioni e/o ostruzioni. Il rene a focaccia è una rara malformazione congenita dell’apparato urinario caratterizzata dalla fusione dei poli superiori, medi ed inferiori di entrambi i reni all’interno della cavità pelvica. Ogni rene è dotato di un proprio sistema escretore, i cui corrispettivi ureteri non attraversano la linea mediana. Nei casi asintomatici il trattamento è di tipo conservativo; il trattamento chirurgico è indicato solo in caso di complicanze urologiche. Il rene a focaccia può associarsi spesso a malformazioni congenite di altri organi o apparati. L’ecografia è la metodica di imaging di prima istanza utile sia per la diagnosi che per il follow-up delle anomalie renali congenite. I principali segni ecografici che suggeriscono la diagnosi di PK sono una voluminosa e lobulata massa renale in sede pelvica, formata dalla fusione dei due reni in assenza di setti. Ogni reni presenta un sistema calico-pielico autonomo e separato, i cui ureteri non oltrepassano la linea mediana e dopo un breve decorso sboccano normalmente in vescica. L’ecografia fornisce, pertanto, informazioni morfologiche e volumetriche, ma anche sulla vascolarizzazione mediante l’utilizzo del Color- e Power-doppler. Metodiche di imaging di secondo livello sono la Tomografia Computerizzata e la Uro-Risonanza Magnetica, utili per un ulteriore conferma diagnostica e per identificare eventuali altre anomalie. La conoscenza delle singole caratteristiche delle varie malformazioni renali è importante per evitare i frequenti errori diagnostici. In questo articolo descriviamo il caso di una paziente di sesso femminile di 14 anni con rene a focaccia, erroneamente diagnosticato come rene a ferro di cavallo in una precedente ecografia dell’addome.
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Lomoro, P., Simonetti, I., Vinci, G. et al. Pancake kidney, a rare and often misdiagnosed malformation: a case report and radiological differential diagnosis. J Ultrasound 22, 207–213 (2019). https://doi.org/10.1007/s40477-018-0331-4
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DOI: https://doi.org/10.1007/s40477-018-0331-4