Kaposiform Lymphangiomatosis (KLA) is a rare and often life-threatening disease. It affects the lymphatic system—a vital network of vessels and tissues that helps manage fluid levels, fight infections, and transport fats. In KLA, the lymphatic vessels grow abnormally and can cause fluid to build up around organs like the lungs or heart. This can lead to breathing problems, bleeding issues, and other serious complications.
Recently, doctors shared a powerful story of a young child with KLA who got better thanks to a medication called trametinib—a treatment usually used for certain types of cancer. Here’s what families should know about this hopeful breakthrough.
The Journey to a Diagnosis
The story begins with a baby boy who seemed healthy at birth but started showing unusual symptoms as he grew: a swollen scrotum, difficulty gaining weight, and eventually a large amount of fluid around his lungs (called a pleural effusion). He also had an enlarged spleen and problems with blood clotting. Several tests ruled out cancer, and he was first diagnosed with a type of lymphatic anomaly called Generalized Lymphatic Anomaly (GLA).
Doctors started him on sirolimus, a drug that helps control abnormal vessel growth. At first, he improved. But after a few months, the problems came back—more fluid in the lungs, more bleeding, and low platelets. Something wasn’t right.
Doctors began to suspect KLA, a more severe condition that can look like GLA at first but behaves much more aggressively.
A Breakthrough with Trametinib
To confirm KLA, the team measured levels of a protein in the blood called Angiopoietin-2 (Ang-2). This protein is often elevated in patients with KLA. The boy’s Ang-2 levels were very high, even while on sirolimus.
So, the doctors switched him to trametinib, a drug that targets a specific pathway in cells (called the MEK pathway) known to be active in some forms of KLA.
The results were dramatic:
- Pleural effusions disappeared
- Splenomegaly (enlarged spleen) resolved
- Ang-2 levels dropped back into the normal range
The child started gaining weight, breathing normally, and even attending daycare like other children his age.
Why This Matters
This is the first documented case, according to authors’ knowledge, where trametinib treatment successfully normalized Ang-2 levels in a KLA patient. It shows that:
- Ang-2 can be a useful marker for diagnosing and tracking KLA
- Trametinib may offer a powerful alternative for patients who don’t respond to sirolimus
- Precision medicine—using targeted treatments based on how a disease works at the molecular level—is changing the game for rare diseases
What Families Should Know
If your child has been diagnosed with a complex lymphatic anomaly like KLA:
- Keep track of symptoms like breathing issues, swelling, or unexplained bleeding
- Ask about biomarker testing, especially Angiopoietin-2 levels
- Talk to your care team about treatment options beyond sirolimus, especially if symptoms return or don’t improve
- Know that new discoveries are emerging—and stories like this one are helping guide the way
While trametinib is not approved specifically for KLA, this case shows it can make a life-changing difference for some patients.
Final Thoughts
KLA is a rare and difficult condition, but new discoveries are offering real hope. Thanks to the hard work of scientists, doctors, and families, we’re learning more about how to treat—and even manage—this complex disease. Trametinib’s success in this case is more than just a clinical milestone; it’s a reminder that breakthroughs are possible, and every child’s story matters.
Reference: McDaniel, C. Griffina,b; Merkle, Svatavaa,b,c; Lacuna, Sophiad; Cooper, Stephaniee; Courtemanche, Rebeccae; Nguyen, Tramd; Le Cras, Timothy D.a,b. Trametinib Normalizes Angiopoietin-2 Levels and Successfully Treats Kaposiform Lymphangiomatosis. Journal of Vascular Anomalies 6(4):p e124, December 2025. | DOI: 10.1097/JOVA.0000000000000124
