Pelvic Kidney: A Review of the Literature

Unraveling Renal Arteries Morphogenesis from Tridimensional Human Embryos Reconstruction

BACKGROUND

During human morphogenesis, the definitive kidneys derive from the metanephros during Carnegie Stage 14 to 23. The pronephros and the mesonephros develop previously and successively to finally lead to the formation of the urinary tract. Renal vascularization, first described in 1912 by Félix using a "ladder theory" model, is highly variable and current available morphogenesis descriptions do not explain all reported anatomical variations. The aim of this work was to study the morphogenesis of the human metanephros and its vascularization by three-dimensional reconstructions of human embryos.

METHODS

Histological sections of 23 human embryos from the Carnegie Collection and 5 human embryos from the French collection (Carnegie stages 14 to 23) were completely digitalized and reconstructed in three dimensions using specific softwares and then analyzed by descriptive method using manual annotation.

RESULTS

In all studied embryos, the mesonephric arteries did not reach the metanephros irrespective to the position of the metanephros during its cranial ascent. Before the end of the cranial metanephros migration (15 embryos), at the level of the aorto-iliac bifurcation, a "primitive" vascularization was shown in 9 of them. The renal artery originated from the primitive iliac arteries for 8 embryos and from the inferior mesenteric artery in one embryo. Further, a capillary cluster emerging from the lateral wall of the aorta and extending toward the metanephros was found in 2 embryos (Carnegie stages 21 and 22). This may correspond to a phenomenon of neoangiogenesis responsible of the definitive renal artery.

CONCLUSIONS

The present study reported the morphogenesis of human renal arteries between Carnegie stages 14 and 23 using an original method of tridimensional computerized reconstructions of historical human embryos. Some original findings, in contradiction with the original Felix's description, may explain the most frequently reported anatomical variations.

Congenital anomalies of the kidney and urinary tract

Congenital Anomalies of the Kidney and Urinary Tract (CAKUT) refer to a range of conditions that affect the kidney and urinary tract. These anomalies can be severe, such as kidney agenesis, or milder, such as vesicoureteral reflux. CAKUT affects over 1% of live births and accounts for 40-50% of cases of chronic kidney failure in children. The pathogenesis of CAKUT is caused by various environmental, genetic, and epigenetic factors that disrupt normal nephrogenesis. Environmental factors that can lead to CAKUT include maternal diabetes, obesity, malnutrition, alcohol consumption, or medications affecting kidneys development. Genetic factors can cause an imbalance in the metanephros and the ureteric bud interaction. Defects in specific genes such as PAX2, TBX18, NRIP1, REX, SIX2, BMP4, and chromosome 17 cause CAKUT. Over 50 genes have been identified as the root cause of this condition, with monogenetic variants causing up to 20% of all cases. CAKUTs can be diagnosed through fetal ultrasonography, but some anomalies may remain undetected. GWASs, Next Generation Sequencing for targeted and whole exome DNA sequencing may provide additional diagnostic methods. This review article highlights some the leading factors that cause CAKUT, which adversely affects kidney development and urinary tract function.

Ectopic Kidney with an Ectopic Ureter Masquerading Adnexal Mass: A Case Report and Literature Review

An ectopic kidney is a rare congenital defect that is often asymptomatic, but can be incidentally discovered during imaging examinations. Moreover, the morphological characteristics and laboratory features of ectopic kidneys are nonspecific, which may lead to misleading diagnostic approaches, particularly when there are additional factors, such as infection, obstruction, or other anomalies. A 43-year-old female presented with a mass in the left adnexal area. She had septate uterus and a history of congenital urinary incontinence. Ultrasound and MRI findings indicated that the mass was a cyst originating from the ovary. However, it is possible that the lump was derived from the urinary system. To confirm the diagnosis, laparoscopy was performed, followed by pathological examination, which confirmed the presence of an ectopic kidney with a single-system ectopic ureter. The patient underwent nephroureterectomy, and her symptoms successfully resolved, leading to a favorable prognosis. This case report highlights a rare case involving an ectopic kidney with a vaginal ectopic ureter that initially presented as an adnexal cyst and caused urinary dribbling. This case emphasizes the importance of early recognition and accurate diagnosis in women with similar symptoms.

A rare case of a combination of ectopic kidney and medial arcuate ligament syndrome: a case report

BACKGROUND

Ectopic kidney and median arcuate ligament syndrome are both rare conditions. The clinical presentation and diagnosis of these conditions are not well studied. There are no reports on the combination of these two rare conditions.

CASE PRESENTATION

We report a 24-year-old woman with fever, dysuria, urinary frequency and left flank pain for two days. The primary diagnoses in the clinic were left acute pyelonephritis and left hydronephrosis due to throbbing pain in the left costovertebral angle and pyuria. However, further computed tomography showed right ectopic pelvic kidney, left renal pelvis dilatation without definite ureteral lesion, good bilateral renal contrast enhancement, and compression of the celiac axis due to obstruction by the median arcuate ligament. Chronic abdominal symptoms were reported by the patient after repeat history taking. The patient's condition was fully explained and discussed with her and her family, but they refused further therapy. After the acute pyelonephritis began improving, the patient was discharged for follow-up at our outpatient clinic.

CONCLUSION

We present an extremely rare case of a combination of two rare conditions: ectopic kidney and median arcuate ligament syndrome. No study to date has reported on the relationship between the two diseases. Given the rarity of the two conditions, no evidence or even a hypothesis exists to explain the possible etiology of their combination. More reports are required to enhance the understanding of these rare conditions.

Robot-assisted laparoscopic pyeloplasty is a valid option for ureteropelvic junction obstruction repair in adults with congenital renal abnormalities: a case series study

BACKGROUND

Congenital renal anomalies are rare but may be associated with obstruction of the ureteropelvic junction. Given the rarity of simultaneous ureteropelvic junction obstruction [UPJO] and renal anomalies in the adult population, there is limited literature on approaching these patients. We report our experience with robotic assisted laparoscopic pyeloplasty for UPJO repair in this subset of patients.

METHODS

Data on adult patients with simultaneous congenital renal abnormalities and UPJO who underwent robotic assisted laparoscopic pyeloplasty between 2008 and 2020 was reviewed. Pre-operative data, intraoperative parameters as well as post-operative data including symptom resolution and radiologic findings were recorded.

RESULTS

Ten patients, 4 female and 6 males, with a mean age of 47 years were identified as having simultaneous congenital renal abnormalities and UPJO. Anomalies identified were horseshoe kidney in four patients, duplex kidney with obstruction of one moiety in two patients, malrotated kidney in two patients, and pelvic kidney in two patients. Eight out of ten were symptomatic at presentation with flank pain being the most common symptom. Eight patients underwent robotic pyeloplasty via the dismembered technique, while two underwent robotic Y-V pyeloplasty. With a mean follow up time of 13 months, 8/9 (88%) symptomatic patients enjoyed symptom resolution. Post-op renogram was available for nine patients and showed resolution of obstruction in all patients (100%). One patient developed a urine leak which was managed successfully with drainage.

CONCLUSIONS

Robotic assisted laparoscopic pyeloplasty is a safe, feasible and effective surgical approach in management of adult patients with concomitant UPJO and renal anomalies.

Ectopic kidney injury due to blunt abdominal trauma

Ectopic kidney is a relatively uncommon anatomic variation that is usually detected incidentally in patients undergoing imaging for an unrelated reason. Most cases are asymptomatic and are often revealed by a complication; however, ectopic kidney is generally associated with higher risk of traumatic injury, urinary tract infection, renal calculi and other urologic conditions. We report the case of a 65-year-old male patient with a post-traumatic renal laceration on a previously undiagnosed ectopic pelvic kidney, with successful conservative treatment.

Laparoscopic Radical Hysterectomy for Endometrial Carcinoma in a Woman with an Ectopic Pelvic Kidney

A 59-year-old post-menopausal female presented with complaints of per vaginal spotting for 3 months. Histopathological examination of contents of dilation and curettage revealed endometrial carcinoma (FIGO stage I), along with benign endocervical polyps. MRI also showed presence of left-sided structure indicative of ectopic pelvic kidney. The patient underwent laparoscopic radical hysterectomy, bilateral salpingo-oophorectomy and bilateral ilio-obturator lymph node dissection. Dissection was started along the left pelvic plane. The left pelvic kidney was seen, and left ureter was located and confirmed below the uterus. The patient withstood the procedure well. Anomalies of pelvic anatomy, such as a malpresentation of the kidney and ureter, may prove as surgical challenges while performing open and laparoscopic surgery. However, in depth preoperative imaging, meticulous intraoperative dissection and proper identification of surrounding structures reduces the risk of such complications.

Neurogenic Bladder-Induced Stone in a Pelvic Kidney of a Caudal Regression Syndrome Patient: Management of a Complex Case

Percutaneous nephrolithotomy (PCNL) is a difficult treatment for treating kidney stones, especially when there are orthopedic or skeletal abnormalities. Here, in a 19-year-old male, we describe a two-step PCNL with a case of caudal regression syndrome (CRS) and a pelvic kidney, with an extremely deformed neurogenic bladder on intermittent catheterization. Our conclusion is that PCNL may be done safely with minimum morbidity in patients with caudal regression syndrome by utilizing adult equipment for heavy stone burdens, allowing full and rapid stone removal.

Incidentalomas Among Healthy Nephrology Fellow Volunteers at POCUS Workshops: A Case Series

A radiographic incidental finding (sometimes called an incidentaloma) is defined as a structure that is unintentionally found during an exam for an unrelated indication. The increased use of routine abdominal imaging is associated with a rising incidence in incidentalomas of the kidney 1. In one meta-analysis, 75% of renal incidentalomas were benign 2. However, the overall prevalence of incidental carcinomas is low at 0.2% 3. With the growing uptake of POCUS, healthy volunteers for clinical demonstrations may find themselves with new findings despite a lack of symptoms 4. Having an incidentaloma discovered during the course of a nephrology POCUS workshop is a unique experience. Herein we report our experiences of having incidentalomas discovered during the course of POCUS demonstrations.

Ectopic Kidney Mimicking Appendicular Abscess

Ectopic kidney is a congenital anomaly of renal position, which is commonly asymptomatic. Symptoms arising from pelvic kidneys can closely mimic pathological processes of nearby organs and vice versa. We report an 18-year-old girl who presented with acute onset of a painful lump in the right iliac fossa. Although the clinical features mimicked an appendicular abscess, the judicious use of cross-sectional imaging aided in the proper diagnosis. Pyonephrosis of a right-sided lumbar kidney was confirmed on further imaging and nephrectomy was performed. This case has been presented to highlight the significance of renal imaging in patients suspected of an appendicular abscess.

Caudal regression syndrome and a pelvic kidney: case report

Caudal regression syndrome (CRS) is a rare congenital variation. A high incidence of renal and genitourinary malformations has been observed in patients with CRS, with the most common being neurogenic bladder and renal agenesis. We report a rare case report documenting both CRS and a pelvic kidney found during a diagnostic magnetic resonance imaging. Although renal anatomy variants are found in patients with CRS, a pelvic kidney is normally not part of the constellation of findings in this malformation. As seen in our patient, a pelvic kidney should be considered in patients suspected of having CRS.

Pelvic kidney with double, venous drainage

An ectopic kidney is defined as an atypically placed kidney, due to improper migration from the fetal pelvis, during embryogenesis. The presented CT scan of 72-year-old male with pain and visible hematuria reveals that the right kidney is located in the pelvis. The ectopic kidney has malrotation with a calcified artery and 2 veins. One draining in the right common iliac vein and the other connected to the left common iliac vein-near the bifurcation of vena cava inferior. Usually, pelvic ectopy is asymptomatic. However, it may lead to elevated blood pressure, increased risk of stone formation, infections, and traumatism, due to the atypical anatomical position. Variations in the anatomy of the kidney and its vascular supply are of clinical importance. It is possible to encounter a radiological, surgical, or cancer case, such as the presented.

Renal artery dissection as an overuse Injury

The diagnosis of renal infarction is often convoluted due to its non-specific presentation. It can mimic disease processes as disparate as pyelonephritis, diverticulitis, or nephrolithiasis. This case is further complicated by the presence of a pelvic kidney with triplicate arterial input. It is difficult to estimate the incidence of pelvic kidneys as the numerous sources vary wildly in their estimations; however, the paucity information, in and of itself, speaks to the rarity of the condition. In this case, a 58-year-old male presents to the emergency department after experiencing sharp, sudden, and severe groin pain while swinging a golf club. The patient was noted to have an abnormally high systolic blood pressure in the 170s and hematuria, but all other initial labs and assessments were unremarkable. An initial computed tomography scan with intravenous contrast of the abdomen and pelvis showed partial necrosis of a pelvic kidney. Follow-up computed tomography angiography revealed that a dissection in one of the arteries supplying the kidney created an infarction and resultant necrosis. Vessel size, location and time between injury and diagnosis made endovascular intervention impractical. The patient was started on aspirin and Plavix, observed for 3 days and sent home.

Persisting subcardinal vein associated with unilateral ectopic pelvic kidney

Absence of left kidney was noted during routine anatomy dissection of a male cadaver of South Indian origin. On examination of the abdomen and pelvic cavities; an ovoid mass of tissue was found in the pelvis, anterolateral to the sacrum. Further dissection revealed the presence of an ectopic left side kidney. The ectopic kidney was lying inferior to the sigmoid colon and anterior to the bifurcation of left common iliac vessel. It was supplied by numerous aberrant vessels from the terminal part of abdominal aorta. One of the renal veins which drain the ectopic kidney was found to be persisting subcardinal vein and it is a novel finding. Such ectopic pelvic kidneys are susceptible to blunt trauma, iatrogenic injuries as well as pathologic manifestations.

A unilateral pelvic kidney with variant vasculature: clinical significance

The incidence of ectopic pelvic kidney accounts for ~1 of 2500 live births. Although pelvic kidneys are most often asymptomatic, they may be associated with several pathologies including hypertension. As pelvic kidney results from a brief interference of the ascension of the developing kidney, it is frequently accompanied by an atypical and variable blood supply. The presence of multiple arteries and veins and their abnormal course and morphology are associated with surgical and radiological significance. Malrotation of the kidney with extrarenal calyces further predisposes the pelvic kidney to recurrent urinary tract infections. This report describes a rare case of a unilateral pelvic kidney with vascular and calyceal variations, and this case is reported to provide additional insight into this variation and its correlation to clinical practice.

Right pelvic kidney during intersphincteric resection for locally advanced rectal cancer: a case report

Background

Simultaneous occurrence of colorectal malignancy with pelvic kidney has been considered a rare phenomenon. A review of the related literature revealed three previous reports of rectal cancer and pelvice kidney.

Case presentation

This case report describe the case of 40-year-old Asian man with complaints of bleeding and a feeling of discomfort in his anus. A colonoscopy revealed a raised large multilobulated mass in his rectum. Multiple biopsies of the lesion were done after detecting a tumor in his rectum 4 cm above the dentate line; a diagnosis of rectal adenocarcinoma was made by pathological examinations. Subsequent investigations, carried out by computed tomography (CT) scans, incidentally showed an ectopic pelvic kidney. Because of the progress of the rectal cancer, our patient was a candidate for neoadjuvant radiotherapy. Six weeks after radiotherapy, he underwent total mesorectal excision (TME) surgery maintaining the ectopic kidney after using a coloanal anastomosis for additional curative surgery. A very low anterior resection surgery was performed to maintain the ectopic kidney. Thereafter, adjuvant chemotherapy was performed.

Conclusions

Due to the proximity of the tumor to the pelvic viscera, especially the ectopic kidney, the probability of inadequate abscission of the lesion in surgery and radiotherapy, as well as complications and localized relapse were increased so that the kidney could be maintained. Carrying out careful pre-treatment examinations can result in maintaining an ectopic kidney and its daily conditioned function dependent on the status of the patient, including the proximity of the ectopic kidney to the tumor, anatomical position, and prior damage. The lesson learned from the present case is that radiotherapy and surgery are possible treatments in the presence of pelvic kidney and rectal cancer without incurring renal damage.

Electronic supplementary material

The online version of this article (10.1186/s13256-019-2151-3) contains supplementary material, which is available to authorized users.