Background: Variations in renal veins are quite common, and most people do not experience issues due to them. However, these variations are important for healthcare professionals, especially in surgical procedures and imaging studies, as precise knowledge of vascular anatomy is essential to avoid complications during medical interventions. The purpose of this study was to expose the frequency of anatomical variations in the renal vein (RV) and detail their relationship with the retroperitoneal and renal regions. Methods: A systematic search was conducted in the Medline, Scopus, Web of Science, Google Scholar, CINAHL, and LILACS databases from their inception until January 2024. Two authors independently carried out the search, study selection, and data extraction and assessed methodological quality using a quality assurance tool for anatomical studies (AQUA). Ultimately, consolidated prevalence was estimated using a random effects model. Results: In total, 91 studies meeting the eligibility criteria were identified. This study included 91 investigations with a total of 46,664 subjects; the meta-analysis encompassed 64 studies. The overall prevalence of multiple renal veins was 5%, with a confidence interval (CI) of 4% to 5%. The prevalence of the renal vein trajectory was 5%, with a CI of 4% to 5%. The prevalence of renal vein branching was 3%, with a CI of 0% to 6%. Lastly, the prevalence of unusual renal vein origin was 2%, with a CI of 1% to 4%. Conclusions: The analysis of these variants is crucial for both surgical clinical management and the treatment of patients with renal transplant and hemodialysis.

Nutcracker phenomenon (NCP) typically refers to the entrapment of the left renal vein (LRV) between the aorta and the superior mesenteric artery. Similar to the classic NCP, the renal vein can also get entrapped between the segmental branches of the renal artery at the renal hilum, which has been referred to as \'renal hilar nutcracker phenomenon (RHNP).\' During routine dissection of a male cadaver of 67 years, the renal veins of both sides at the renal hilum were seen between the segmental branches of renal arteries, which we identified as the \'renal hilar nutcracker phenomenon.\' The disposition of the rest of the perihilar structures was normal. \'Renal hilar nutcracker phenomenon\' can have similar clinical presentation like that of the nutcracker phenomenon. Hence, knowledge of such anatomical variation at the renal hilum is desirable.
Terminu „spragtuko fenomenas“ įprastai apibūdinamas kairiosios inkstų venos įstrigimas tarp aortos ir viršutinės mezenterinės arterijos. Panašiai į klasikinį „spragtuko fenomeno“ atvejį, inkstų vena taip pat gali įstrigti ir tarp inkstų arterijos segmentinių atšakų ties inkstų sienelėmis. Šis reiškinys vadinamas inkstų hilariniu spragtuko fenomenu ir angliškai trumpinamas RHNP. Per 67 metų vyro lavono skrodimą buvo pastebėta, kad inkstų venos abiejose pusėse ties inkstų sienelėmis buvo išsidėsčiusios tarp inkstų arterijų segmentinių atšakų. Mes tai įvardijome „inkstų hilariniu spragtuko fenomenu“. Visos likusios perihilarinės struktūros išsidėstymas buvo normalus. Inkstų hilarinis spragtuko fenomenas kliniškai gali pasireikšti panašiai į spragtuko fenomeną. Todėl būtų naudinga įgyti daugiau žinių apie šią anatominę inkstų sienelių variaciją.

OBJECTIVE: Assess whether a Retroaortic left renal vein (RLRV) affects vertebral osteophyte formation in the lumbar spine, compared to normal anatomy left renal vein.
METHODS: We conducted a retrospective case-control study. Computed tomography (CT) scans of individuals with a RLRV (study group) were compared to age- and gender-matched normal anatomy CT scans (control group). L1 to L4 vertebral levels were appreciated for: left renal vein level, osteophyte presence and the aorta-vertebral distance (AVD) at the left renal vein level. Univariate analyses were conducted using Chi-square test and Fisher\'s test for categorical variables, and Student\'s t-test for continuous variables. Logistic regression was used for multivariate analyses.
RESULTS: A total of 240 patients were included in the study - equally distributed between the study and control groups. Normal anatomy left renal veins traversed the spine only at the L1 and L2 levels. RLRVs traversed the spine in all L1-L4 levels, mostly at the L3 and L2. Osteophyte prevalence at the level of left renal vein was significantly higher in the study group, compared with the control group [OR 2.54, P = 0.01]. Mean AVD was greater in the study group [9.2 mm ±3.6 mm Vs. 3.5 mm ± 2.6 mm, P < 0.001]. Increased AVD was found to be associated with a higher chance of osteophyte presence at the level of the left renal vein [OR 1.282, P = 0.025].
CONCLUSIONS: Osteophytes are more prevalent at the level of the RLRV variant compared to the normal anatomy. Furthermore, the RLRV is characterized by a lower lumbar level compared to the normal anatomy.
CONCLUSIONS: This anatomic variation could assist in further understanding of osteophyte formation.

Renal angiomyolipoma (AML) is a rare benign tumor of the kidney, often detected incidentally on radiological images as the presence of macroscopic fat characterizes them. In the majority of the cases, they are usually sporadic. Despite their benign nature, venous invasion, a rare occurrence in renal AMLs, poses management challenges. We present a case of bilateral renal AML in a 52-year-old female with a right renal vein and hepatic inferior vena cava invasion.

We present two cases of multiple anatomical variations of the renal and gonadal vessels. The first case presented duplication of the renal vein and the presence of an accessory renal artery. However, the most interesting fact, in this case, was that the right gonadal vein emptied into the inferior right renal vein instead of ending in the inferior vena cava as would typically be the case. In the second case, we also found an accessory renal artery and the right gonadal vein emptied at the exact junction between the right renal vein and the inferior vena cava. Clinicians and surgeons should be familiar with anatomical variations to provide an accurate diagnosis during preoperative studies and to avoid surprises in abdominal surgical procedures.
Este estudo apresenta dois casos de variação anatômica múltipla de vasos renais e gonadais. O primeiro caso apresentou uma duplicação da veia renal e a presença de uma artéria renal acessória. Porém, o fato mais interessante nesse caso foi a veia gonadal direita desembocar na veia renal direita inferior em vez de terminar na veia cava inferior, como seria o normal. No segundo caso, além de também encontrarmos uma artéria renal acessória, a veia gonadal direita desembocava no exato ponto de junção entre a veia renal direita e a veia cava inferior. Clínicos e cirurgiões devem estar familiarizados com a presença de possíveis variações dos vasos renais e gonadais, sendo um conhecimento imprescindível para obter um diagnóstico mais preciso e para evitar surpresas em procedimentos cirúrgicos abdominais.

Knowledge of the anatomical variations of the visceral branches of the abdominal aorta is important information for planning any surgeries in the region. We present here a rare constellation of variations of visceral vessels around the kidneys with a brief review of the recent literature. On the right side, an accessory renal artery was observed originating just distal to the main renal artery. The middle suprarenal artery was absent on the right side and there were two inferior suprarenal arteries originating from a branch of the main right renal artery. On the left side, the testicular artery had an arched course anterior to the left renal vein mimicking an unusual variety of nutcracker phenomenon. The right kidney was drained by two renal veins into the inferior vena cava. Knowledge of the coexistence of such complex anatomical variations might be helpful for clinicians during diagnostic and therapeutic procedures.
O conhecimento das variações anatômicas dos ramos viscerais da aorta abdominal é uma informação importante para o planejamento de qualquer cirurgia nessa região. Neste relato, apresentamos um raro conjunto de variações de vasos viscerais ao redor dos rins, bem como uma breve revisão da literatura recente. No lado direito, foi observada uma artéria renal acessória originando-se distal à artéria renal principal. Não havia artéria suprarrenal média no lado direito, e havia duas artérias suprarrenais inferiores originando-se de um ramo da artéria renal direita. No lado esquerdo, a artéria testicular apresentava um curso arqueado anterior à veia renal esquerda, simulando uma variedade incomum do fenômeno do quebra-nozes. O rim direito era drenado por duas veias renais para a veia cava inferior. O conhecimento da coexistência de tais variações anatômicas complexas pode ser útil para os clínicos durante os procedimentos diagnósticos e terapêuticos.

To examine the prognostic significance of perinephric fat, renal sinus fat, and renal vein invasion in patients with pT3a renal cell carcinoma (RCC) by histologic type.
A population-based retrospective cohort study of patients with pT3aN0M0 RCC was performed using Surveillance, Epidemiology, and End Results (SEER) data for the years 2010 through 2019. Cox proportional hazards models were used to examine the relationship between pT3a subclassification groups and cancer-specific survival (CSS) by histological subtype (clear cell, papillary, chromophobe, and other).
The cohort consisted of 10,170 patients with pT3a RCC, including 8,446 (83.0%) with clear cell RCC and 1,724 (17.0%) with nonclear cell RCC (nccRCC). Median follow up was 36 months. Differences in CSS by pT3a subclassification groups were observed in all histological subtypes but were most pronounced in nccRCC, specifically papillary RCC. Compared to perinephric fat (PF) invasion only, renal vein (RV) invasion (HR = 4.9, 95%CI: 2.5-9.3, P < 0.01), renal sinus fat invasion (HR = 3.0, 95%CI: 1.4-6.2), RV and PF invasion (HR = 7.5, 95%CI: 3.5-16.0), and combination of all three characteristics (HR = 4.4, 95%CI: 1.2-15.5) were associated with worse CSS in patients with papillary RCC.
We examined the prognostic role of pT3a staging subclassifications in RCC by histologic subtype and observed survival differences, particularly in papillary RCC. Our findings highlight the need to refine pT3a staging criteria to help guide individualized, multimodal treatment strategies for locally advanced RCC.

The renal vein is an exceptional location for leiomyosarcoma, an aggressive malignant tumor of smooth-muscle origin with a poor prognosis. We report the case of a 55-year-old female patient who consulted for left flank pain that had been present for 6 months. A CT scan revealed a 9.4cm left retroperitoneal mass in contact with the psoas muscle, left kidney, stomach, spleen, left colon and extending up to the pancreas, raising the suspicion of a tumour originating in the retroperitoneal tissues. A biopsy revealed a smooth-muscle cell tumour with a degree of malignancy difficult to define. The patient underwent a monobloc left compartmentectomy, which led to the diagnosis of leiomyosarcoma of the left renal vein. A review of the literature on these rare tumours in this location is presented.

The gonadal veins, responsible for draining from the paired gonads (testes in males and ovaries in females), exhibit variations in anatomy. Traditionally, the right gonadal vein directs its drainage into the inferior vena cava, while the left gonadal vein typically connects to the left renal vein. However, in the case of a 45-year-old woman diagnosed with a non-functional right kidney who underwent a right nephrectomy, an intraoperative observation revealed an unusual configuration: the right gonadal vein (ovarian) was found to drain directly into the right renal vein instead of its usual route into the inferior vena cava. This case report aims to elucidate this anomalous finding and provide a literature review on the prevalence of such anomalies in the existing research. This case report aims to raise awareness about the atypical drainage patterns of gonadal veins and underscore the importance of meticulous dissection of hilar renal vessels.

BACKGROUND: No consensus has been reached on operative procedures since a limited case series of robot-assisted inferior vena cava thrombectomy (RA-IVCT) and robot-assisted radical nephrectomy (RA-RN) have been described.
METHODS: The clinical data of 21 patients who underwent RA-IVCT and RA-RN were retrieved from the database. Preoperative preparation was used for assessment of the tumour. Surgical procedures were recorded, and operative skills were summarised.
RESULTS: The median IVC clamping time was 23 min, and IVC wall invasion was pathologically found in 2 cases. The mean postoperative hospital stay was 8.4 days and most patients recovered to full ambulation and oral feeding on the fourth day. None of the patients had liver or kidney dysfunction at the last follow-up (median, 24 months).
CONCLUSIONS: RA-IVCT presents technical challenges to surgeons. IVC control is an important part of the surgical process and different sides require different techniques.