Although regarded as benign, angiomyolipomas may grow such that kidney function is impaired or the blood vessels may dilate and burst, leading to bleeding.

Whether associated with these diseases or sporadic, angiomyolipomas are caused by mutations in either the TSC1 or TSC2 genes, which govern cell growth and proliferation.

PEComas are themselves a kind of mesenchymal tumour which involves cells that form the connective tissue, cardiovascular, and lymphatic systems.

[3] Three methods of scanning can detect angiomyolipomas: ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI).

However, accurate measurements are hard to make with ultrasound, particularly if the angiomyolipoma is near the surface of the kidney (grade III).

MRI is safer than CT, but many patients (particularly those with the learning difficulties or behavioural problems found in tuberous sclerosis) require sedation or general anaesthesia, and the scan cannot be performed quickly.

[6] Both minimal fat AMLs and 80% of the clear-cell type of RCCs display signal drop on an out-of-phase MRI sequence compared to in-phase.

[6] Some centers may perform preventative selective embolisation of the angiomyolipoma if it is more than 4 cm in diameter, due to the risk of hemorrhage.

[9] People with tuberous sclerosis are advised to have yearly renal scans, though patients with very stable lesions could be monitored less frequently.

A side effect of this treatment is postembolisation syndrome, severe pain and fever, but this is easily managed and lasts only a few days.

[3] A ruptured aneurysm in an angiomyolipoma leads to blood loss that must be stopped (though embolisation) and compensated for (through intravenous fluid replacement).

Therefore, removal of the affected kidney (nephrectomy) is strongly discouraged, though may occur if the emergency department is not knowledgeable about tuberous sclerosis.

The destroyed kidney tissue often causes postembolisation syndrome, which manifests as nausea, vomiting, fever, and abdominal pain, and lasts a few days.

[9] Patients with kidney loss should be monitored for hypertension (and treated for it if discovered) and avoid nephrotoxic drugs such as certain pain relievers and intravenous contrast agents.

Angiomyolipomas larger than 5 cm and those containing an aneurysm pose a significant risk of rupture, which is a medical emergency, as it is potentially life-threatening.