Bilateral renal aneurysms

A 56-year-old patient, asymptomatic, diagnosed with right breast cancer with ipsilateral axillary lymph node extension confirmed by histopathology, underwent contrast-enhanced computed tomography (CT) to determine the extent of the disease and lesions with avid contrast enhancement at the bilateral renal level were found.

Unenhanced and contrast-enhanced CT showed, in the upper pole of the right kidney, a 13 mm saccular aneurysm, without thrombi or calcifications, originating from the right anterior segmental artery. This CT also showed, at the level of the middle third of the left kidney, a 14 mm diameter saccular aneurysm, originating from the left anterior segmental artery (Figures 1a and 1b).

The patient in our case did not meet any of the risk factors for rupture of aneurysms. It was decided to continue with annual surveillance with magnetic resonance imaging, in which no changes in the diameter of the aneurysms, evidence of thrombosis or development of calcifications were observed (Figures 2a, 2b, 2c and 2d).

Eighteen months after her diagnosis, the patient presented pain in the right flank. A renal Doppler ultrasound showed a well-defined oval lesion with a Yin-Yang sign in the upper pole of the right kidney measuring 14x14 mm. In the left kidney, at the level of the middle third, another lesion with similar characteristics was observed, measuring 14x13 mm. No free fluid or data of aneurysmal rupture were observed (Figures 3a and 3b).

Renal artery aneurysm (RAA) is a rare vascular abnormality with an incidence of 0.01 to 0.09%. The most common age of presentation is 40 to 50 years, and it predominantly affects females [1]. It is associated with collagenopathies, vasculopathy, fibromatosis, iatrogenic causes, trauma, and atherosclerotic disease, among others. They are frequently unilateral, specifically on the right side. 20% of cases are bilateral and are associated with fibromuscular dysplasia. Renal aneurysms can be multiple in up to 30% of cases. In 85%, its location is extraparenchymal, at the bifurcation of the main renal artery or the first-order branches. They are commonly asymptomatic and detected incidentally in imaging studies. Its clinical manifestations include difficult-to-control arterial hypertension, haematuria, flank pain, palpable mass, hypovolemic shock, and death [2].

In image features, its morphological characteristics depend on its morphological classification, whether saccular, fusiform, dissecting, or infrarenal. Of these, the most frequent are saccular, constituting between 60 and 90%, followed by fusiform 20% and dissecting 10%.

In ultrasound, they are lesions found in the renal vascular tract, well-defined and anechoic, with or without wall calcifications, and hypervascular on colour Doppler with the characteristic Yin–Yang sign. Similarly, in tomography and magnetic resonance imaging, they are well-defined lesions, with or without wall calcifications, which avidly enhance with contrast medium and in the angiographic phases. Rundback et al. [3] proposed an arteriographic classification system that divides renal aneurysms into three types: Type I, are saccular and emerge from the main trunk of the renal artery or proximally from a large segmental artery; Type II, is fusiform, located in the main renal artery; Type III, refers to intraparenchymal aneurysms affecting small segmental or accessory arteries.

There are multiple therapeutic management options for RAA: standard surgical, laparoscopic, or endovascular through exclusions with stents or embolisations, always individualising each case to offer optimal management. Factors to consider for therapeutic management are those predisposing to rupture [4]: absence of calcification or incomplete calcification, dissecting aneurysms, aneurysms that cause renal ischemia, diameter greater than 3 centimetres, flank pain, high blood pressure, pregnancy and progressive increase in its diameter in follow-up imaging studies.