From the Guidelines
Angiomyolipoma of the kidney should be treated with mTORC1 inhibition as first-line therapy for tumors requiring non-urgent treatment, especially in patients with tuberous sclerosis complex (TSC) and a substantial bleeding risk 1.
Key Considerations
- The treatment approach for angiomyolipoma should prioritize minimizing the risk of chronic kidney disease (CKD) and preserving kidney function.
- mTORC1 inhibitors have been shown to reduce the size and growth rate of TSC-associated angiomyolipomata, as well as the risk of nephrectomy and CKD 1.
- Interventional radiological and surgical procedures, such as selective arterial embolization and partial nephrectomy, may be considered in patients who are haemodynamically unstable or have failed medical therapy, but these options carry a higher risk of CKD.
Treatment Recommendations
- For patients with TSC and angiomyolipoma, mTORC1 inhibition is recommended as first-line treatment for tumors requiring non-urgent treatment, especially those with a substantial bleeding risk 1.
- In patients with growing angiomyolipomata (>3cm in diameter), mTORC1 inhibition should be considered, although the evidence is weaker (level D, weak) 1.
- For patients with TSC who have undergone kidney transplantation, mTORC1 inhibition-based therapy may be considered on an individual basis, taking into account the presence of TSC-associated lesions 1.
Monitoring and Follow-up
- Regular monitoring with ultrasound or CT scans every 6-12 months is recommended to check for growth and assess the response to treatment.
- Patients with TSC should be closely monitored for signs of bleeding or other complications, and medical therapy should be adjusted accordingly.
From the Research
Definition and Classification of Angiomyolipoma
- Angiomyolipoma (AML) is the most common benign tumor of the kidney, consisting of blood vessels, smooth muscle, and fat components in varying proportions 2.
- AML is divided into the sporadic type and tuberous sclerosis complex (TSC)-associated type, with TSC-associated AML developing at a younger age and exhibiting a faster growth rate 2.
- AMLs are classified as classic AML, fat-poor AML, and epithelioid AML, with epithelioid AML showing aggressive behavior and leading to distant metastasis and mortality 2.
Diagnosis and Management of Angiomyolipoma
- Computerized tomography is the standard diagnostic method for renal AML, while definitive diagnosis is made by histopathology 3.
- Active surveillance is the suggested management for small AML, with clinical intervention indicated when there is a substantial risk of rupture 2, 4.
- Treatment options include partial nephrectomy, transcatheter arterial embolization, and mammalian target of rapamycin (mTOR) inhibitor treatment, with nephron-sparing approaches preferred to preserve kidney function 2, 4, 5.
- High-risk cases, such as renal AML in women of childbearing age, those with growth >0.25 cm/year, intralesional aneurysms >5 mm, and clinically significant symptoms, may qualify for active treatment 3.
Treatment Outcomes and Complications
- Nephron-sparing surgery for sporadic renal angiomyolipomas offers preservation of renal function and is associated with acceptable complication and low local recurrence rates 5.
- The major complication of AML is intra-tumoral or retroperitoneal hemorrhage due to rupture, which may be serious and life-threatening 2.
- mTOR inhibitors, such as everolimus, may be safe and effective in treating angiomyolipoma tumor burden in patients with tuberous sclerosis complex 4.