Renal arteriovenous malformation

A tumor-like renal arteriovenous malformation on 18F-PSMA-1007 PET/CT: a case report

Background

Renal arteriovenous malformations (rAVMs) are congenital abnormal pathways between renal arteries and veins that are rare in the general population. It is often misdiagnosed as malignant renal tumors with abundant blood supply, and the definitive diagnosis primarily relies on angiography. Multimodality imaging, including contrast-enhanced computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET)/CT plays an important role in the differential diagnosis of renal space-occupying lesions.

Case presentation

A 56-year-old man presented with abdominal distension, loss of appetite, and back pain without obvious cause 2 years ago, without nausea vomiting, or frequent urination. Gastroscopy and colonoscopy showed multiple polyps in the duodenum and colon. Abdomen contrast-enhanced CT revealed a mass of 1.6 × 1.4 cm in the left kidney, which was considered to be a malignant tumor. PET/CT was performed for further diagnosis; the 18F-fluorodesoxyglucose (18F-FDG) PET/CT scan showed mild uptake in the left renal mass, while no uptake of 18F- prostate-specific membrane antigen (PSMA) was observed. Following a multidisciplinary discussion, the possibility of renal AVMs was considered and subsequently confirmed by renal angiography as the diagnosis. Then, selective segmental renal artery embolization was performed for treatment.

Conclusion

Renal AVMs are extremely rare in clinical practice. Due to limited research on the application of 18F-FDG and 18F-PSMA PET/CT to renal AVMs, its role remains largely unexplored. With the increasing popularity of PET/CT imaging, comprehensive imaging of the disease has become indispensable. We report the first case of PSMA PET/CT imaging in renal AVMs, and when PSMA expression is absent in a renal mass, the possibility of renal AVMs should be considered.

Endovascular Treatment Failure of Renal Arteriovenous Malformation due to an Extrarenal Feeding Artery: A Case Report

Renal arteriovenous malformation (RAVM) is a rare pathology. It may present with heamturia, hypertension, and congestive heart failure. Digital subtraction angiography (DSA) is the standard diagnostic choice, and endovascular embolization is a preferred procedure of management in most cases. The feeding branches of RAVM are reported to originate from renal arteries. In this report, a 43-year-old female with recurrent massive hematuria and left flank pain was described. Renal angiography revealed double renal arteries supplying the left kidney and multiple renal arteriovenous fistula formation around the renal pelvis. Embolization with coils and gelfoam was performed after which her hematuria subsided. One month later, the patient was readmitted to our hospital due to the relapse of massive hematuria following heavy physical activities. DSA found another feeding artery of the RAVM originating from the aorta around the 4th lumbar vertebra. After embolization of this arterial feeder, hematuria settled. There was no recurrence during a 10-month follow-up. To our knowledge, this is the first case of RAVM with an extrarenal feeding artery, and omission of this scenario can lead to treatment failure.

Renal arteriovenous malformation and venous thrombosis: a tumour-like presentation

Renal arteriovenous malformation is a primarily congenital renal vascular abnormality. It is usually diagnosed incidentally on imaging, and the most common subtype is 'cirsoid', consisting of multiple, enlarged arterial feeders interconnecting with draining veins. We present a 74-year-old woman with an incidental finding of what was at first considered a hypervascularised kidney tumour but turned out to be a left intrarenal arteriovenous malformation associated with a left renal vein thrombosis. Selective endovascular embolisation was performed. The cause-consequence relationship between the arteriovenous malformation and the thrombosis is unique. To our knowledge, no such case has ever been reported.

Arteriovenous malformation with a renal mass: A rare association

Renal arteriovenous malformation can be rarely associated with a renal mass. A vigilant approach and careful planning is required to tackle both the pathologies in form of preoperative coil embolization followed by a minimally invasive radical nephrectomy.

Arteriovenous fistula-related renal bleeding 5 days after percutaneous renal biopsy

A 32-year-old Japanese woman was admitted to our hospital for evaluation of microscopic hematuria with a positive family history. Percutaneous renal biopsy was performed under real-time ultrasound guidance using a 16-gauge automated needle and three specimens were obtained. She had no risk factors for hemorrhage. However, macroscopic hematuria developed from 5 days after biopsy and persisted for 4 days. Her Hb decreased markedly from 15.0 to 8.1 g/dL. Enhanced computed tomography revealed urinary tract hematoma, while the early arterial phase showed inflow of contrast medium into the left renal vein from a pseudoaneurysm on a branch left renal artery. Renal transcatheter arterial embolization was performed using platinum microcoils and the arteriovenous fistula was occluded. The patient did not require blood transfusion. Severe renal bleeding that causes urinary tract hematoma usually occurs within 24 h after renal biopsy, but the possibility of late-onset renal bleeding should be kept in mind.