Angiomyolipoma: Types, Causes, Symptoms, Diagnosis, Treatment, Prognosis and Risk Factors

They are mesenchymal tumors of the benign, non-cancerous type, which are composed of three types of cells:

  1. The vascular cells
  2. The immature cells of smooth muscle.
  3. The fat cells.

These tumors occur mainly in the kidneys but are occasionally found in the liver.

The mediastinum, the heart, the spermatic cord, the vaginal wall, the fallopian tubes, the oral cavity, the pharynx, the nasal cavity, the skin, and the colon rarely appear in the mediastinum.

The old medical literature refers to angiomyolipomas with the name hamartomas or choristomas.


The exact causes of angiomyolipomas are unknown, but the researchers suggest that a sporadic genetic mutation in the TSC1 and two genes may be the cause.

Research has reported that these tumors arise from cells called epithelioid cells that surround blood vessels.

It is known that multiple angiomyolipomas occur in the context of tuberous sclerosis, which is a rare and systemic genetic condition that gives rise to benign tumors in the brain.


As well as in other vital organs, but in the case of colon angiomyolipoma, an association with tuberous sclerosis is not reported.

In general, angiomyolipomas are associated with other genetic disorders such as von Recklinghausen disease, neurofibromatosis, the von Hippel-Lindau, Sturge-Weber syndromes, and autosomal dominant polycystic kidney disease.

Research indicates that the influence of hormones plays a vital role in the formation of angiomyolipomas because it occurs more frequently in women.

So it increases its size during pregnancy, its appearance is after puberty, and the microscopic examination shows the activity of progesterone receptors.


Angiomyolipomas are usually asymptomatic; however, depending on where they occur, different symptoms can be observed, such as:


The symptoms of benign angiomyolipomas of the kidney can be the following:

  • Back or flank pains.
  • Sickness.
  • Vomiting
  • Anemias.
  • Hypertension.
  • Chronic kidney diseases.
  • Shock (approximately 20% of patients who develop symptoms also develop shock)


This condition is asymptomatic, and the underlying skin shows a typical appearance since it is a dermal, solitary, and a little deep tumor.

Sometimes it can be painful to the touch.

Reproductive organs

It is of rare presentation in ovaries, fallopian tubes, and the spermatic cord; usually, they do not present symptoms when the tumor enlarges, or the blood vessels rupture.

Symptoms can be caused such as pelvic pain, genital bleeding, prolapse of the pelvic organs, and urinary symptoms such as incontinence, and frequency, which often become confused with other pathologies of gynecological type.


Approximately 60% of patients are symptomatic and have abdominal pain.

Pharynx, oral and nasal cavity

The angiomyolipomas located in this area are infrequent.

The symptoms are usually nasal obstruction and, in some cases, recurrent epistaxis, rhinorrhea, mass sensation or rhinopharyngeal foreign body, and snoring.


Most colon tumors are small, and there may be no symptoms.

The symptoms of colon angiomyolipomas include the following:

  • Colonic tumors usually show up as polyps, and some have pedicles.
  • Abdominal pain and discomfort are present.
  • Blood is rarely seen in the stool, but they result in anemia when they occur.
  • There are very irregular bowel movements and diarrhea or constipation.
  • Distension and abdominal swelling.
  • In the case of large tumors, intestinal obstructions may occur, and bleeding may lead to tissue death.

In general, tumors greater than 4 cm can compress the organs and surrounding structures and cause problems in their functioning, becoming symptomatic.


Angiomyolipomas are tumors with defined characteristics, so they usually have no drawbacks in their diagnosis, mainly when they are located in the kidney and soft tissues.

However, special attention must be paid to the differential diagnosis when its appearance is on a mucosal surface such as the oral cavity.

The diagnosis of angiomyolipomas is based on:

  • A complete physical examination with the evaluation of the medical history.
  • An ultrasound or abdominal and pelvic computed tomography is non-invasive procedure excellence.
  • Analysis of fecal samples and urine.
  • In the case of the colon, a colonoscopy allows for observing the inner lining of the colon and rectum.
  • Lower gastrointestinal series, with combinations of X-rays and barium to visualize the intestine.
  • Exploratory laparoscopy.

Although these modalities can be used to make an initial diagnosis, histological diagnosis is definitive.

The tissue for this diagnosis is recommended to obtain by open tumor biopsy and tissue biopsy.

Thanks to the tumor’s tissue biopsy and the findings shown in the microscope, the pathologist makes his definitive diagnosis.


In most tumors, because they are asymptomatic, they are not surgically removed.

But there is the advantage that if he opted for surgical abstinence, there is no possibility of tumor malignancy.

But when these increase in size or cause some symptoms, it is required:

In the case of colon angiomyolipomas, analgesics are recommended when there is pain.

Surgery with complete excision can result in complete healing.

Among the techniques for extirpation are known:

  1. Small tumors can be removed when a colonoscopy and a biopsy are performed to ensure they are not malignant.
  2. A partial colectomy or an intestinal resection is performed when a portion of the colon is damaged.
  3. Another possible treatment is the embolization of the tumor.

Treatment for renal angiomyolipomas may initially include prescription medications such as everolimus (Afinitor). Whose mechanism of action is to block the rapamycin protein affecting many processes involved in cell growth.

It is suggested that even when the existence of an angiomyolipoma is asymptomatic, treatment should be indicated when the growth of more than 3 cm in diameter is observed.

Another treatment option is embolization, a technique by which blood vessels are sealed.

This technique is usually preventive, and its use is suggested in angiomyolipomas with diameters greater than 4 cm in diameter to reduce the risk of rupture of the vessels and bleeding.

Surgeries can be used for total removal, and in some more severe cases, it may be necessary until the kidneys are removed.

I am considering the rarity of these tumors in places such as the heart, liver, spermatic cord, vaginal walls, fallopian tubes, pharynx, skin, and oral and nasal cavities.

Almost always, the inclination of the treatment is the total surgical excision, and given the occasional recurrence, a postoperative evolutionary control must be performed.

This allows treatment and diagnosis in a single step. In the case of an accurate diagnosis of angiomyolipomas, there is no specific recommendation about treatment follow-up or prevention.

Finally, the treatment of underlying or associated conditions should be administered.

Angiomyolipoma prognosis

  • The prognosis of a colon angiomyolipoma will depend on the severity of the symptoms. It will also depend on the patient’s state of health, the existence of an association with tuberous sclerosis, and the response that the body offers to therapy.
  • Generally, tumors of small size tend to provide the patient with a better prognosis than patients with tumors with diameters greater than 4 cm. In this way, the forecast decreases as the size increases, increasing the probability of bleeding.
  • Usually, in the case of small and solitary tumors, the prognosis of tumors is excellent, with surgical excision or with the appropriate treatment, since these tumors are benign.
  • It is impossible to prevent angiomyolipomas, but the risk that over time becomes symptomatic or endangers the patient’s life can be reduced by using medication administration and embolization techniques for some cases.
  • However, in the case of renal angiomyolipomas, the prognosis decreases if it complicates kidney function and makes dialysis necessary.
  • Patients with small, asymptomatic angiomyolipoma tumors should see their doctor frequently to follow up and measure the diameter of the angiomyolipoma.

Risk factor’s

The sex

Studies have reported a higher incidence of angiomyolipoma in female patients.


Studies show that the ages presented by patients at the time of diagnosis ranged from 25 to 55 years, which is rarely diagnosed in children.

Hormone influence

It was observed that during pregnancy, an increase in the size of the angiomyolipoma suggests the possibility of a hormonal influence on growth.