BACKGROUND: Evaluation of multidrug-resistant hypertension in young adults requires consideration of uncommon secondary etiologies, including renovascular disease and congenital renal vascular anomalies. Renal arteriovenous malformations (rAVMs) represent a rare cause of secondary hypertension, accounting for less than 0.1% of renal vascular abnormalities. They most commonly present with hematuria, flank pain, or, in high-flow lesions, high output cardiac failure. Hypertension as the principal manifestation is uncommon.

CASE REPORT: We describe a 33-year-old woman with longstanding uncontrolled hypertension requiring 5 antihypertensive agents who presented for evaluation of refractory blood pressure control. Initial duplex ultrasound and angiography identified a large complex left renal lesion associated with dysmorphic parenchyma and aberrant arterial and venous architecture without a history of trauma, intervention, or prior renal surgery, consistent with a congenital vascular malformation. Diagnostic computed tomography angiography demonstrated a 6.5×6.5×5.5 cm arteriovenous malformation. Given the lesion’s size and vascular complexity, endovascular embolization was deemed not technically feasible. The patient subsequently underwent elective simple nephrectomy without intraoperative complication. Histopathology confirmed a congenital high-flow rAVM with extensive parenchymal distortion. Postoperatively, the patient exhibited marked improvement in blood pressure control, eliminating the need for antihypertensive medication.

CONCLUSIONS: This case illustrates an uncommon presentation of severe drug-resistant hypertension in a young patient likely attributed to a large congenital rAVM. Congenital renal vascular malformations should be considered in the differential diagnosis of refractory hypertension. Surgical intervention remains an important therapeutic option when endovascular treatment is contraindicated or considered unlikely to preserve functional renal parenchyma.

Keywords: Congenital Abnormalities, Hypertension, Renal, Hypertension, Renovascular, Nephrectomy