A kidney typically receives its arterial supply from a single RA. However, RA anatomical variations beyond classical patterns are not uncommon, with a prevalence of up to 30.00% [4]. Multiple renal arteries are recorded, with doubled, triplet, and four renal arteries accounting for 18.67%, 1.80%, and 0.01% respectively in a systemic review [7]. The prevalence of multiple renal arteries shows no obvious distinction between the left and right side [4, 7]. AA is the common origin of accessory renal arteries with a ratio of 88.39%, followed by RA of 8.34%, and other origins such as celiac trunk, common iliac, and superior mesenteric artery are rare [7, 8]. Accessory renal arteries are further classified into hilar and polar arteries, depending on the place they penetrate the kidney. In this case, the ARA enters the kidney through the lower pole, therefore, can also be defined as the right inferior polar artery, sharing a prevalence of 8.20% and 3.48% in two studies [4, 8].

Variations of TA have a prevalence of 20% and are usually observed in terms of origin, length, course, and number [3]. In this case, the aberrant TA originates from midway along the course of ARA to the renal hilum. Literature reported that the likelihood of the TA arising from an accessory renal branch is statistically around 9.6% (16/166) [2].

The morphological variations of the present case can be traced back to embryological development. By the fifth week, kidneys are developed from the metanephros and the ureteric diverticulum on both sides of the pelvic region, and pronephros and mesonephros will atrophy [9]. During the formation of the renal and vasculature nine pairs of lateral mesonephric arteries are present, classified into cranial, middle, and caudal groups [10]. The median group of arteries from the third to fifth mesonephric arteries evolve into the definitive renal arteries, and a caudal group from the sixth to ninth forms testicular arteries [3, 11]. If any group of mesonephric arteries persists, accessory renal arteries will arise [9, 10]. In this case, the site and size of RA are normal (fits the classical description) while the ARA courses anteriorly to the IVC and joins the kidney near the inferior pole. From the functional standpoint, since TA originates from ARA in this case, if ARA courses posterior to IVC like RA, there won’t be any space for TA to originate from ARA, and this specific person would be devoid of the right TA. Therefore, for TA to originate from ARA without any compression or blocking, ARA can only course anterior to IVC.

As for the gonads, they develop on the posterior abdominal wall at the lumbar region and receive mesonephric arteries superior to the renal vascular pedicle [2, 6]. Then they descend, receiving vasculature from more inferior branches while the above disappear, and finally, the caudal group gives rise to definitive testicular arteries [6, 12], and the remanence of the cranial group would lead to a high origin of the TA [10]. In the present case, TA originates from the inferior margin of the right ARA, and we speculate that it is the additional branch of the middle group of mesonephric arteries (if remnant, will turn into accessory renal arteries) that gives rise to aberrant gonadal arterial origin (Fig. 3, hypothesis 1). Another possible explanation for aberrant gonadal arterial origin is also related to ARA. In the period of cephalic migration of the kidney, there is an overlap and a combination of arteries supplying the ascending kidney and the descending testis [13]. Literature suggests that the variation of the TA is likely an embryological mistake resulting in the existence of an ARA [11]. In the present case, the abnormal RA may increase the likelihood of misconnection in mesonephric arteries. If arterial pedicles are mismatched, the future TA may originate from the ARA (Fig. 3, hypothesis 2).

The morphology and variations in the renal and testicular vascular structures are significant in any type of renal or testicular surgery [2, 3, 14]. This is because the surgical area is always complicated and has high operation requirements, especially in laparoscopic surgeries. The variants of the TA occur frequently and usually are accidentally discovered during the surgery, so their abnormal origin and course around the kidney may lead to unexpected serious hemorrhage [14]. Therefore, the knowledge of such vascular variations is crucial for surgery to repair renal stenosis, renal infarctions, and renal hypertension, as well as other urological surgeries [15].

Describing such anatomical variations also helps radiologists with the correct interpretation of image examinations. When performing indicated angiographic tests, the radiologist’s knowledge of variation increases the possibility of detecting variation and the accuracy of the assessment. Further examination of the abnormality with magnetic resonance imaging and venography can more clearly identify the origin and branching of the variant, providing a complete reference for the surgical process to increase the success rate of surgery [2].

In conclusion, the present case describes an aberrant origin of the TA originating from a right ARA which arises inferiorly and crosses anteriorly to the inferior vena cave, and finally supplies the right kidney below the renal hilum, whereas the RA originates from the lateral surface of AA, coursing posteriorly to IVC, and enters the renal hilum as usual. And above variations were traced back to their embryological development. Awareness of such variations is crucial to avoid complications like hemorrhage during surgery. Additionally, understanding these variations is important for radiologists in interpreting imaging studies and for improving the success rates of kidney transplants.