Lymphangioleiomyomatosis – Diagnostics – Overview of Information and Clinical Research

Lymphangioleiomyomatosis, or LAM, is a rare lung disease that creates cysts in the lungs, kidneys, and lymphatic system. Diagnosing this condition early can help patients access treatments that slow disease progression and improve quality of life, though the process can be challenging because symptoms often mimic more common respiratory problems.

Introduction: Who Should Be Tested for LAM

Women who experience unexplained breathing problems, especially during their childbearing years, should consider being evaluated for LAM. This rare condition almost exclusively affects women between the ages of 20 and 40, though symptoms can appear at any age during the reproductive years. Because LAM is so uncommon and its symptoms mirror those of more common lung diseases like asthma or chronic bronchitis, many women live with symptoms for several years before receiving the correct diagnosis.^[1]

If you experience shortness of breath that gradually worsens over time, especially combined with chest pain or chronic cough, it’s important to seek medical evaluation. Many women with LAM first discover they have the condition after experiencing a sudden, sharp chest pain and difficulty breathing—signs that point to a collapsed lung (also called pneumothorax), which is the most common complication of LAM. Over half of all women with LAM will experience at least one collapsed lung, and for many, this frightening event becomes the catalyst that leads doctors to investigate further and ultimately identify the disease.^[1]

Women who have been diagnosed with tuberous sclerosis complex (TSC), a rare genetic disorder that causes tumors to grow in various organs, should be particularly vigilant about lung health. Between 30 and 80 percent of women with tuberous sclerosis also develop LAM, making regular screening essential for this group. The risk increases with age—while 27 percent of women with TSC have LAM by age 21, this number jumps to 81 percent for those over 41 years old.^[1]^[3]

Early diagnosis matters because it opens the door to treatments that can stabilize lung function and prevent further damage. Without proper diagnosis, symptoms continue to progress, lung function declines, and complications become more likely. The average delay between first symptoms and diagnosis is typically five to six years, time during which the disease continues to damage the lungs unchecked.^[6]

Classic Diagnostic Methods

Diagnosing LAM requires a combination of different tests and procedures, as no single test can definitively identify the condition on its own. Healthcare providers begin with a thorough physical examination and discussion of symptoms, then move through progressively more detailed testing to build a complete picture of what’s happening in your body.

Physical Examination and Medical History

The diagnostic journey typically starts in a doctor’s office, where a healthcare provider will listen to your breathing sounds with a stethoscope and ask detailed questions about your symptoms. They’ll want to know when your breathing problems began, whether they’ve gotten worse over time, if you’ve experienced chest pain, and whether you have any family history of lung disease or tuberous sclerosis. In early stages of LAM, the physical exam may appear completely normal, which is one reason why the condition can be so difficult to identify initially.^[7]

Lung Function Testing

One of the first specialized tests your doctor will order is a pulmonary function test, which measures how well your lungs are working. During this test, you’ll breathe into a device called a spirometer that measures the amount of air you can inhale and exhale, as well as how quickly you can move air in and out of your lungs. This test helps doctors understand whether your airways are obstructed and how much your lung capacity has been affected by the disease.^[1]^[5]

A related test called a six-minute walk test evaluates how your lungs perform during physical activity. You’ll walk for six minutes while a device monitors the oxygen levels in your blood. This simple test provides valuable information about how LAM affects your ability to function in daily life and whether supplemental oxygen might help you breathe more comfortably.^[5]

Blood Oxygen Testing

Doctors will check the levels of oxygen in your blood using a test called pulse oximetry, where a small clip-like device is placed on your fingertip. This painless test instantly shows whether your blood is carrying enough oxygen to meet your body’s needs. Low oxygen levels can indicate that the cysts in your lungs are preventing proper oxygen absorption. Some patients may need this test performed during exercise or while sleeping to see if oxygen levels drop during activity or rest.^[1]^[7]

Blood Tests

A specialized blood test can measure levels of a protein called VEGF-D (vascular endothelial growth factor-D). Women with LAM often have elevated levels of this protein in their bloodstream. While this test alone cannot diagnose LAM, high VEGF-D levels combined with other findings can support the diagnosis and may even help doctors decide whether a lung biopsy is necessary. This blood test offers a less invasive way to gather diagnostic information.^[1]^[7]

⚠️ Important

Because LAM symptoms closely resemble those of asthma, chronic bronchitis, and emphysema, many women are initially misdiagnosed with these more common conditions. If you’ve been treated for asthma or another lung disease but your symptoms aren’t improving or continue to worsen, ask your doctor about the possibility of LAM. A proper diagnosis is essential to receive the right treatment.

Imaging Studies

Imaging tests create pictures of the inside of your lungs, allowing doctors to see the characteristic cysts that LAM creates. A standard chest X-ray may be performed first, but it often appears normal in early LAM or shows only subtle changes that could be mistaken for other conditions.^[7]

The most important imaging test for diagnosing LAM is a high-resolution computed tomography scan (HRCT or CT scan). This sophisticated type of X-ray creates detailed, three-dimensional images of your lungs by taking multiple pictures from different angles. The CT scan can reveal the thin-walled cysts throughout the lungs that are the hallmark of LAM. These cysts appear as small, round, dark spaces scattered throughout the lung tissue. The pattern and distribution of these cysts is so characteristic that in many cases, a CT scan showing typical cyst patterns combined with elevated VEGF-D levels can confirm the diagnosis without requiring a lung biopsy.^[1]^[5]

Because LAM can also affect the kidneys and lymphatic system, your doctor may order an abdominal CT scan, MRI scan, or ultrasound to check for kidney tumors called angiomyolipomas or enlarged lymph nodes. These benign fatty tumors occur in about 30 to 40 percent of women with sporadic LAM and in most patients with TSC-associated LAM. Finding these tumors provides additional evidence supporting a LAM diagnosis.^[3]^[5]

Lung Biopsy

In some cases, when imaging and other tests don’t provide a clear answer, doctors may recommend a lung biopsy. This procedure involves removing a small sample of lung tissue so it can be examined under a microscope. The biopsy allows pathologists to look for the abnormal smooth muscle-like cells that are characteristic of LAM. There are different ways to obtain lung tissue, including through a bronchoscopy (where a thin tube with a camera is passed through your mouth or nose into your airways) or through a surgical procedure.^[1]^[5]

However, because biopsies carry some risk and can be uncomfortable, many doctors now rely on the combination of characteristic CT scan findings and elevated VEGF-D levels to make the diagnosis, reserving biopsy for cases where the picture remains unclear. This approach spares many women from unnecessary invasive procedures.^[5]

Genetic Testing

For women suspected of having LAM associated with tuberous sclerosis, genetic testing may be performed to look for mutations in the TSC1 or TSC2 genes. These genes normally act as tumor suppressors, keeping cells from growing out of control. When mutations occur in these genes, cells multiply unchecked, leading to both tuberous sclerosis and LAM. Genetic testing can help distinguish between TSC-associated LAM and sporadic LAM, which has implications for family members and genetic counseling.^[1]^[7]

Additional Diagnostic Tests

Depending on your symptoms, doctors may order additional specialized tests. An echocardiogram uses sound waves to create images of your heart, helping doctors assess whether LAM has affected your heart function. An exercise test measures how your heart and lungs respond to physical activity, providing information about your overall fitness and whether oxygen therapy might help during exertion.^[5]

Diagnostics for Clinical Trial Qualification

Women interested in participating in clinical trials for LAM treatments will typically need to undergo a comprehensive diagnostic evaluation to determine if they meet the study’s enrollment criteria. Clinical trials have specific requirements to ensure that participants truly have LAM and that their disease severity falls within the range being studied.

Confirming the Diagnosis

Before enrolling in a clinical trial, researchers need definitive proof that you have LAM. This usually requires either a characteristic CT scan showing the typical cyst pattern throughout the lungs, or in some cases, proof of LAM through a previous lung biopsy. Some trials accept elevated VEGF-D blood levels combined with typical imaging findings as sufficient evidence, while others may require tissue confirmation.^[5]

Baseline Lung Function Testing

Clinical trials almost always require detailed pulmonary function testing before enrollment. These baseline measurements establish how well your lungs are working at the study’s start, which allows researchers to determine later whether the treatment being tested has helped stabilize or improve lung function. Trials may require specific lung function values—for instance, some studies only enroll patients with moderate disease, while others focus on patients with more severe lung damage. The forced expiratory volume in one second (FEV1), which measures how much air you can force out of your lungs in one second, is often a key measurement used to determine eligibility.^[13]

Oxygen Level Assessment

Trials typically measure your blood oxygen levels both at rest and during physical activity. The six-minute walk test, performed while monitoring oxygen saturation, helps researchers understand how LAM affects your daily functioning. Some trials only accept patients who require supplemental oxygen, while others focus on those who don’t yet need oxygen support. These criteria help ensure that the study population is appropriate for the treatment being tested.

Imaging Requirements

Most clinical trials require a recent high-resolution CT scan, typically performed within a few months before enrollment. This imaging serves as a baseline to compare against future scans during and after the treatment period. The scan helps researchers document the extent of cyst formation and lung damage at the study’s start. If you have kidney angiomyolipomas, researchers may also require imaging of your kidneys to measure tumor size before treatment begins, as some LAM treatments can affect these growths.^[12]

VEGF-D Blood Testing

Many clinical trials measure VEGF-D levels in your blood before treatment starts. This protein is elevated in most women with LAM, and changes in VEGF-D levels during treatment may indicate whether the therapy is working. Having a baseline measurement allows researchers to track how the treatment affects this important biomarker over time.^[13]

Exclusion Criteria Testing

Clinical trials have safety requirements that protect participants from potential harm. Before enrollment, you’ll undergo various tests to ensure you don’t have conditions that would make the experimental treatment unsafe for you. These might include blood tests to check your liver and kidney function, blood cell counts, and cholesterol levels. Some trials exclude women who are pregnant or planning to become pregnant, requiring pregnancy tests before enrollment. If the trial involves medications that affect the immune system, you may need tests to check for underlying infections that could become dangerous during treatment.^[13]

Quality of Life Assessments

Researchers want to understand not just how LAM affects your lungs, but also how it impacts your daily life and well-being. Before joining a trial, you may complete questionnaires about your symptoms, energy levels, ability to perform daily activities, and emotional health. These assessments provide baseline information that helps researchers determine whether the treatment improves patients’ quality of life, not just their test results.

Additional Screening Tests

Depending on the specific trial, you might need additional specialized testing. Some studies examine how LAM cells behave at the molecular level, requiring extra blood samples. Others might use advanced imaging techniques like PET scans or specialized lung function tests that aren’t part of routine clinical care. Each trial has unique requirements based on what the researchers are trying to learn about the disease and the treatment being studied.

⚠️ Important

Participating in a clinical trial can provide access to new treatments before they’re widely available, but it requires commitment to regular testing and follow-up visits. All tests performed as part of the trial are typically provided at no cost to you. If you’re interested in clinical trials, talk with your LAM specialist about whether any current studies might be appropriate for your situation.

Prognosis and Survival Rate

Prognosis

The outlook for women with LAM has improved dramatically over recent decades as understanding of the disease has grown and effective treatments have become available. However, the course of LAM varies considerably from one woman to another, making it difficult to predict exactly how the disease will progress in any individual case. For some women, LAM advances slowly over many years, while others experience more rapid deterioration of lung function.

Several factors influence how LAM progresses. Women who are still in their reproductive years, before menopause, tend to experience faster decline in lung function compared to postmenopausal women. This observation has led researchers to believe that hormones, particularly estrogen, play a role in disease progression. Pregnancy can sometimes worsen LAM symptoms, and the disease often gets worse in women taking medications that contain estrogen. These patterns suggest that the hormonal environment affects how aggressively the abnormal cells grow and damage lung tissue.^[1]^[3]

In all cases, lung function tends to decrease over time as more cysts form and healthy lung tissue is gradually destroyed. The rate of this decline varies, but monitoring lung function through regular pulmonary function tests helps doctors track disease progression and adjust treatment accordingly. Many women will eventually require supplemental oxygen to maintain adequate blood oxygen levels, first during physical activity and sleep, and later throughout the day. Despite this progression, many patients can continue to live active, fulfilling lives with appropriate medical management.^[3]

The availability of sirolimus, the first FDA-approved medication for LAM, has changed the outlook for many patients. This drug can help stabilize lung function and slow the rate of decline, though it doesn’t cure the disease or reverse existing damage. When patients stop taking sirolimus, lung function typically begins declining again at the previous rate. Other complications like kidney tumors, lymphatic problems, and recurrent collapsed lungs also affect prognosis, though these can often be managed with appropriate interventions.^[10]^[12]

Survival Rate

Thanks to advances in diagnosis and treatment, survival rates for LAM have improved significantly. Current estimates suggest that the median survival for patients with LAM is more than 20 years after diagnosis. This means that half of all patients live longer than 20 years following their diagnosis, and many live even longer.^[3]

More detailed survival statistics paint an encouraging picture. Research shows that the transplant-free survival probability—meaning the percentage of patients who are alive without needing a lung transplant—is approximately 94 percent at five years after diagnosis, 85 percent at 10 years, 75 percent at 15 years, and 64 percent at 20 years. These numbers represent a dramatic improvement compared to earlier decades, before effective treatments became available. They reflect both better early diagnosis and the benefits of modern therapies that can slow disease progression.^[3]

It’s important to understand that these statistics represent averages across all LAM patients, and individual outcomes vary widely. Some women maintain relatively stable lung function for many years, while others progress more quickly. Factors like age at diagnosis, rate of lung function decline, response to treatment, and whether the LAM is associated with tuberous sclerosis all influence individual prognosis. Regular monitoring and early intervention when complications arise can help optimize outcomes.

For women with advanced LAM who experience severe lung damage and respiratory failure, lung transplantation remains an option. Many LAM patients who receive lung transplants go on to live for many additional years with their new lungs. However, because the abnormal LAM cells don’t originate in the lungs themselves, the disease can potentially recur even in transplanted lungs, though this happens slowly and doesn’t necessarily affect transplant success.^[7]^[10]

#1 Clinical Trials Search in Europe