Knowra Lymphangioleiomyomatosis Lymphangioleiomyomatosis Lymphangioleiomyomatosis (LAM) is a rare disease in which abnormal smooth muscle-like cells proliferate, damaging lung tissue and sometimes affecting lymphatic vessels and kidneys. It is associated with mutations in the TSC1 or TSC2 genes and occurs mainly in women.
TSC2 : A gene encoding tuberin, a protein that helps restrain cell growth through the mTOR pathway. TSC2 mutations commonly drive LAM cell growth by weakening this restraint.
Tuberous sclerosis complex : A genetic disorder caused by pathogenic variants in TSC1 or TSC2, producing benign tumors in multiple organs. LAM may occur as part of this disorder or arise without its other manifestations.
High-resolution computed tomography : A CT imaging technique that produces detailed cross-sectional views of lung structure. It can reveal the diffuse, thin-walled lung cysts characteristic of LAM.
Pulmonary Langerhans cell histiocytosis : A smoking-associated lung disease in which Langerhans cells cause nodules and cysts, mainly in the upper lungs. Its cyst distribution and smoking association differ from the typically diffuse cysts of LAM.
mTOR : A protein kinase that regulates cell growth, metabolism, and survival in response to nutrients and other signals. Loss of TSC1 or TSC2 restraint activates this pathway in LAM cells.
Smooth muscle : Involuntary muscle tissue found in structures such as blood vessels, airways, and the digestive tract. LAM cells resemble smooth muscle cells, though they have distinctive abnormal growth behavior.
Vascular endothelial growth factor D : A protein involved in lymphatic vessel development and growth that can be measured in blood. An elevated blood level can support a LAM diagnosis when lung imaging shows cysts.
Birt-Hogg-Dubé syndrome : An inherited disorder caused by FLCN variants, associated with skin lesions, kidney tumors, and lung cysts. It is a genetic cause of lung cysts that can resemble LAM on imaging.
Pulmonary cyst : An abnormal air-filled space in the lung surrounded by a defined wall. Diffuse pulmonary cysts are the characteristic structural damage caused by LAM.
Lymphatic system : A network of vessels, nodes, and organs that returns tissue fluid to the bloodstream and supports immune function. LAM can involve lymphatic structures as well as the lungs and kidneys.
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