HLRCC is a rare, inherited condition that causes benign skin tumors and uterine fibroids and increases your risk of an aggressive form of kidney cancer called renal cell carcinoma.

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is a rare condition that causes benign (noncancerous) tumors to develop on your skin. The tumors, which are called leiomyomas, contain smooth muscle tissue. Women with this condition can also develop uterine leiomyomas (fibroids).

HLRCC also increases your risk of developing a type of kidney cancer called renal cell carcinoma (RCC).

The outlook for people with HLRCC is considered good when the condition only affects their skin and uterus. People with HLRCC who develop RCC are at high risk of developing an aggressive, metastatic cancer that causes poor outcomes.

Symptoms of HLRCC can vary widely from person to person, even among members of the same family. Some people with HLRCC won’t develop any symptoms.

The most common symptom of HLRCC is the development of skin tumors called leiomyomas. These benign tumors form in muscle tissue around a hair follicle. They usually show up on your arms, legs, chest, and stomach. They look like small bumps that may be skin-colored, brown, or red. They can be painful to touch.

Most females with HLRCC also develop leiomyomas in the uterus, also known as uterine fibroids. Uterine fibroids can cause symptoms such as:

  • heavy menstrual periods
  • menstrual clots
  • bleeding between periods
  • pelvic pressure or fullness
  • pelvic pain
  • swelling of the abdomen
  • increased urination
  • pain during intercourse

About 10%–16% of people with HLRCC develop RCC.

Symptoms of RCC may include:

  • a lump in your abdomen
  • blood in your urine
  • unexplained weight loss
  • lower back pain
  • loss of appetite
  • fatigue

HLRCC is an inherited condition and is passed down in families. It’s caused by mutations in the fumarate hydratase (FH) gene. The FH gene provides your body with instructions to make an enzyme called fumarase. Mutations may result in a buildup of a molecule called fumarate in your body. This buildup of fumarate is thought to contribute to the development of leiomyomas.

HLRCC is inherited in an autosomal dominant pattern. This means that only one copy of the mutated gene is enough to cause the condition. Children born with two mutated copies of the FH gene have a different condition called fumarase deficiency, which is typically fatal in infancy.

In some cases, new mutations in the gene can occur in people with no history of the condition in their family.

The biggest risk factor for HLRCC is having a family history of the condition. Inheriting one copy of the mutated gene is enough to develop the condition. So, if one parent has the disease-causing variant, children have a 50% chance of inheriting the condition. HLRCC affects all sexes.

HLRCC is a rare condition that has been reported in about 300 families worldwide. Researchers suggest that it may be underdiagnosed.

People assigned female at birth with HLRCC can develop fibroids that affect their ability to have children. Due to symptoms like painful menstruation and heavy bleeding, you may require a hysterectomy at an early age.

HLRCC also increases your risk of developing RCC, an aggressive form of kidney cancer.

Your doctor may suspect HLRCC based on the presence of leiomyomas and a family history of HLRCC.

To help with a diagnosis, a doctor will ask for a detailed medical and family history. They’ll ask about your symptoms and conduct a physical examination.

A doctor may also remove a small sample of skin tissue to observe under a microscope. This is called a skin biopsy. The biopsy can confirm if the skin bumps are leiomyomas or something else.

Tests are also available to measure the activity of FH in your body. Lower activity of FH often means you have HLRCC.

You should contact a doctor if any atypical skin growths or rashes appear on your skin.

If you have a family history of HLRCC, it’s important to visit a doctor for regular skin, uterine, and kidney examinations.

If you’ve already received a diagnosis of HLRCC, you should visit with your doctor regularly for an MRI to identify kidney tumors. The HLRCC Foundation notes that MRI surveillance for HLRCC should begin at 8 years of age and continue throughout life.

Leiomyomas on your skin that aren’t painful generally don’t require treatment. A dermatologist can help treat any leiomyomas that cause pain by removing them surgically or with cryoablation (freezing the skin lesion) or CO2 laser ablation.

A gynecologist can help treat uterine leiomyomas (fibroids). Treatment may include gonadotropin-releasing hormone agonists and pain relievers. The fibroids can also be removed surgically. In some cases, full removal of your uterus (hysterectomy) is recommended.

Treatment for RCC usually includes:

  • surgery to remove the tumors
  • radiation
  • chemotherapy
  • targeted therapies

It’s not always possible to prevent HLRCC, but there are prenatal genetic tests available if the condition runs in your family.

Testing should be considered for anyone with a personal or family history of skin leiomyomas, uterine fibroids, or RCC. Genetic counseling can help you understand your risk and options for testing and management.

Researchers also recommend that anyone at a higher risk of having HLRCC undertake regular skin, uterine, and kidney examinations. Early detection can improve outcomes.

With treatment, people with HLRCC characterized by skin leiomyomas and uterine fibroids have a good outlook. Most people with HLRCC never get kidney cancer, and many will go through life never even knowing they have HLRCC.

But, people with HLRCC who develop kidney cancer have a poorer outlook. Once a kidney tumor is detected on an MRI, doctors recommend removing it with surgery right away because HLRCC-related kidney cancer is often highly aggressive and can spread quickly to other parts of the body.

In general, the earlier RCC is diagnosed and treated, the better your outlook.

In one study of 185 people with HLRCC, the average age of symptomatic RCC diagnosis was 44, and median survival was 21 months. Survival for people who received a diagnosis of early stage RCC was significantly longer than those with a diagnosis of late stage RCC.

The majority of people with HLRCC won’t get kidney cancer, but screening for it throughout life is essential since early detection can help improve your outlook.