Medical & Surgical Urology
Open Access

Pathophysiology of Angiomyolipomas Disease and its Diagnosis

Vinky Ferni^{* *}Correspondence: Vinky Ferni, Department of Surgery, University of Milan, Milan, Italy, Email:

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Description

The most typical benign tumour of the kidney is angiomyolipoma. Despite being benign, angiomyolipomas can develop to the point where kidney function is compromised or where the blood vessels enlarge and break, causing bleeding. Angiomyolipomas are frequently found in Tuberous Sclerosis patients, who typically have several angiomyolipomas affecting both kidneys. They are frequently observed in female patients with the uncommon lung condition lymphangioleiomyomatosis. Angiomyolipomas are uncommon in other organs and less frequently discovered in the liver. Angiomyolipomas are brought on by mutations in either the Tuberous sclerosis Complex 1 (TSC1) or Tuberous Sclerosis Complex 2 (TSC2) genes, which control cell development and proliferation, whether they are spontaneous or connected to these illnesses. They are made up of fat cells, smooth muscle cells, and blood vessels.

Pathophysiology

Angiomyolipomas are tumours made up of perivascular epithelioid cells, which are similar to epithelial cells and are found surrounding blood vessels. The term "PEComa" refers to this type of tumour, which stands for perivascular epithelioid cell. Older literature may have classified them as choristomas (benign tumours made up of normal cells in the incorrect position) or hamartomas (benign tumours made up of cells in their correct location but producing a disorganised mass). PEComas are a specific type of mesenchymal tumour that contain cells from the circulatory, lymphatic, and connective tissue systems. Variable ratios of vascular cells, immature smooth muscle cells, and fat cells make up an angiomyolipoma. The names angio-, myo-, and lip- originate from these three elements in that order. The prefix "-oma" denotes a tumour. Angiomyolipomas often develop in the kidney, while they have also been seen to develop in the liver, ovary, fallopian tubes, spermatic cord, palate, and colon on occasion. Based on the angiomyolipoma's location within the kidney, the Maclean imaging categorization system for renal angiomyolipomas is used.

Diagnosis

Computed Tomography (CT), Magnetic Resonance Imaging (MRI), and ultrasound are the three scanning techniques that can find angiomyolipomas. It is common to use ultrasound, which is more sensitive to the fat in angiomyolipomas than to the solid ones. However, ultrasonography measures are difficult to take accurately, especially if the grade III angiomyolipoma is close to the surface of the kidney. CT is quick and detailed, and it enables precise measuring.

However, it puts the patient at risk for radiation exposure as well as the risk that a contrast dye used to help with the scanning could injure the kidneys. Although MRI is less risky than CT, many patients (especially those with the behavioural or learning issues associated with tuberous sclerosis) need sedation or general anaesthetic, which slows down the scan process.The presence of fat is not diagnostic because other kidney tumours might also contain fat. It can be challenging to distinguish a fat-poor angiomyolipoma from a Renal Cell Carcinoma (RCC).

When compared to an in-phase MRI sequence, an out-of-phase MRI sequence exhibits a signal decline in minimum fat angiomyolipomas and 80% of the clear-cell type of RCCs. As a result, a biopsy may be necessary to diagnose a lesion that is expanding at a rate of more than 5 mm per year. When Angiomyolipomas (AML) are discovered accidentally, Tuberous Sclerosis Complex (TSC) should be taken into account, especially in people between the ages of 18 and 40 and in those who have bilateral angiomyolipomas.

AML-related haemorrhages have a 20%–50% probability of occurring in people with TSC, and of those haemorrhages, 20% are life-threatening. TSC professional clinicians conduct a thorough physical examination, which may include dermatologic and ophthalmologic examinations, as well as a CT or MRI of the brain. A high-resolution CT of the lungs and pulmonary function tests are part of the lymphangioleiomyomatosis screening process.