How to Manage Angiomyolipoma: A Review of Current Evidence and Practice
Angiomyolipoma (AML) is a benign tumor of the kidney that consists of blood vessels, smooth muscle cells, and fat cells. AML can occur sporadically or in association with tuberous sclerosis complex (TSC), a genetic disorder that causes multiple benign tumors in various organs. AML can cause symptoms such as flank pain, hematuria, hypertension, or renal failure. AML can also rupture and cause life-threatening bleeding.
The management of AML depends on several factors, such as the size, location, number, and growth rate of the tumors, the presence or absence of TSC, the patient's age, comorbidities, and preferences, and the availability of treatment options. The main goals of management are to prevent or treat complications, preserve renal function, and improve quality of life.
In this article, we will review the contemporary experience in the management of AML based on the latest evidence and practice guidelines. We will discuss the indications, advantages, disadvantages, and outcomes of different treatment modalities, such as active surveillance (AS), embolization, surgery, and pharmacotherapy.
AS is a conservative approach that involves regular monitoring of AML with imaging tests (such as ultrasound or computed tomography) and clinical evaluation. AS is recommended for asymptomatic patients with small (< 4 cm) or stable AMLs who have low risk of complications or progression. AS is also suitable for elderly patients with comorbidities who are not candidates for invasive treatments.
AS has several benefits, such as avoiding unnecessary interventions, preserving renal function and parenchyma, reducing costs and morbidity, and maintaining quality of life. AS is associated with a low rate of failure (< 5%) and a slow and consistent growth rate (0.088 cm/year) of AMLs[^1^]. However, AS requires compliance and adherence to follow-up protocols, which may vary depending on the size and number of AMLs, the presence or absence of TSC, and the patient's preferences. AS also carries a risk of missing or delaying the diagnosis of malignant transformation or rupture of AMLs.
Embolization is a minimally invasive procedure that involves injecting a substance (such as coils, particles, glue, or alcohol) into the blood vessels that supply AMLs to block their blood flow and induce necrosis. Embolization is indicated for symptomatic patients with large (> 4 cm) or growing AMLs who have high risk of complications or progression. Embolization is also an option for patients who are not candidates for surgery or who refuse surgery.
Embolization has several advantages, such as being effective in reducing tumor size and symptoms, preserving renal function and parenchyma, avoiding general anesthesia and hospitalization, and having low complication rates (< 10%). Embolization can also be repeated if needed. However, embolization has some drawbacks, such as being technically challenging in some cases (such as multiple or complex AMLs), causing post-embolization syndrome (such as fever, pain, nausea, or hematuria), requiring pre-embolization angiography (which exposes the patient to radiation and contrast agents), and having a risk of recurrence or incomplete necrosis of AMLs.
Surgery is an invasive procedure that involves removing AMLs either partially (nephron-sparing surgery) or completely (radical nephrectomy). Surgery is indicated for symptomatic patients with large (> 4 cm) or growing AMLs who have high risk of complications or progression. Surgery is also an option for patients who have failed or are not suitable for other treatments.
Surgery has several benefits, such as being definitive in curing AMLs,
preventing recurrence or malignant transformation,
and improving survival in some cases (such as ruptured AMLs).
Surgery can be performed either open or laparoscopically,