LAM Diagnosis

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Your healthcare provider will diagnose LAM based on your medical history and the results from diagnostic tests and procedures. You may also see a pulmonologist (a healthcare provider specializing in lung diseases and conditions) who has experience providing care to people who have LAM.

Your healthcare provider will ask you about your medical history to see whether you have symptoms of LAM. They may ask how long you have had symptoms and whether your symptoms have become worse over time.

Your provider may order tests to measure how well your lungs are working and determine whether your lungs are delivering enough oxygen to your blood.

Chest CT scan

For an accurate diagnosis, a high-resolution computed tomography (HRCT) scan is essential. It creates detailed pictures of your lungs and the inside of your chest. Computers can combine these pictures to create three-dimensional (3D) models showing the size, shape, and position of your lungs and other structures in your chest. Your healthcare provider may diagnose you with LAM if the chest HRCT shows thin-walled cysts (fluid-filled pockets) in your lungs.

Chest X-ray

A chest X-ray is a fast and painless imaging test to look at the structures in and around your chest.

A chest X-ray may look normal in the early stages of LAM. As the disease gets worse, the X-ray may be used to find cysts in your lungs and monitor any changes over time. Your healthcare provider may use a chest X-ray to look for complications of LAM, such as fluid in your lungs or air in the chest cavity that collapses your lung (a pneumothorax).

Lung function tests

Lung function tests can help your healthcare provider determine how well your lungs are working. These tests may help diagnose certain lung conditions or diseases, including LAM.

Blood tests

Your healthcare provider may order blood tests, such as a test for vascular endothelial growth factor D (VEGF-D) that looks for increased VEGF-D levels in your blood. Higher levels of VEGF-D can stimulate the growth of new blood vessels, which can enable the cells that cause LAM cells to spread in the body. About 70% of patients with LAM have raised VEGF-D levels.

If other tests cannot diagnose LAM, your healthcare provider may recommend a lung biopsy, but only when an absolutely certain diagnosis is required.

• A lung biopsy removes small pieces of your lung to check for LAM cells. Your provider may do an open lung biopsy, which involves making a cut in your chest wall between your ribs. With a transbronchial biopsy, your provider inserts a long tube down your windpipe and into your lungs. Whenever possible, the transbronchial biopsy is the preferred approach. Your healthcare provider can also diagnose LAM using results from biopsies of other tissues, such as the lymph nodes.
• Video-assisted thoracoscopic surgery (VATS) may be done to remove small pieces of your lung to check for LAM cells, if your provider suspects LAM but is not able to diagnose using a traditional open lung or transbronchial biopsy. In the VATS procedure, your provider makes several small cuts in your chest wall and inserts a small, lighted tube with tools and a camera on the end. The camera takes pictures of the lungs to guide your provider while they do the biopsy.

Your healthcare provider may need to order other diagnostic tests to determine whether you have a related condition called tuberous sclerosis complex (TSC), which can lead to LAM, or to rule out another condition.

• CT scans or magnetic resonance imaging (MRI) scans of your head can help your provider determine whether you have TSC. People with TSC often have tumors in the brain and other parts of the body.
• Genetic testing identifies mutations (changes) in your TSC1 and TSC2 genes to help your provider confirm that you have LAM and not another lung disease.
• Thoracentesis uses a needle to collect fluid samples from the lining of your lungs. If your chest imaging tests show that you have fluid building up in the space between the lung and the chest wall (called pleural effusions), your provider may order thoracentesis to collect this pleural fluid for analysis.