MedGen

Lymphangioleiomyomatosis (LAM) is a condition that affects the lungs, the kidneys, and the lymphatic system. The lymphatic system consists of a network of vessels that transport lymph fluid and immune cells throughout the body. Lymph fluid helps exchange immune cells, proteins, and other substances between the blood and tissues.

LAM is found almost exclusively in women. It often occurs as a feature of an inherited syndrome called tuberous sclerosis complex. When LAM occurs alone it is called isolated or sporadic LAM.

Signs and symptoms of LAM most often appear during a woman's thirties. Affected women have an overgrowth of abnormal smooth muscle-like cells (LAM cells) in the lungs, resulting in the formation of lung cysts and the destruction of normal lung tissue. They may also have an accumulation of fluid in the cavity around the lungs (chylothorax).

The lung abnormalities resulting from LAM may cause difficulty breathing (dyspnea), chest pain, and coughing, which may bring up blood (hemoptysis). Many women with this disorder have recurrent episodes of collapsed lung (spontaneous pneumothorax). The lung problems may be progressive and, without lung transplantation, may eventually lead to limitations in activities of daily living, the need for oxygen therapy, and respiratory failure. Although LAM cells are not considered cancerous, they may spread between tissues (metastasize). As a result, the condition may recur even after lung transplantation.

Women with LAM may develop cysts in the lymphatic vessels of the chest and abdomen. These cysts are called lymphangioleiomyomas. Affected women may also develop tumors called angiomyolipomas made up of LAM cells, fat cells, and blood vessels. Angiomyolipomas usually develop in the kidneys. Internal bleeding is a common complication of angiomyolipomas. [from MedlinePlus Genetics]

Infiltration of smooth muscle-like cells in lymph vessels as well as the lung (pleura, alveolar septa, bronchi, pulmonary vessels and lymphatics as well as lymph nodes, especially in posterior mediastinum and retroperitoneum). Focal emphysema can develop because of airway narrowing, and the thoracic duct may be obliterated. Pulmonary lymphangiomyomatosis may lead to multiple small cysts with a hamartomatous proliferation of smooth muscle in their walls. [from HPO]

Tuberous sclerosis complex (TSC) involves abnormalities of the skin (hypomelanotic macules, confetti skin lesions, facial angiofibromas, shagreen patches, fibrous cephalic plaques, ungual fibromas); brain (subependymal nodules, cortical tubers, and subependymal giant cell astrocytomas [SEGAs], seizures, intellectual disability / developmental delay, psychiatric illness); kidney (angiomyolipomas, cysts, renal cell carcinomas); heart (rhabdomyomas, arrhythmias); and lungs (lymphangioleiomyomatosis [LAM], multifocal micronodular pneumonocyte hyperplasia). Central nervous system tumors are the leading cause of morbidity and mortality; renal disease is the second leading cause of early death. [from GeneReviews]

A rare, multiple cystic lung disease characterized by progressive cystic destruction of the lung and lymphatic abnormalities, frequently associated with renal angiomyolipomas (AMLs). [from ORDO]

Tuberous sclerosis complex (TSC) involves abnormalities of the skin (hypomelanotic macules, confetti skin lesions, facial angiofibromas, shagreen patches, fibrous cephalic plaques, ungual fibromas); brain (subependymal nodules, cortical tubers, and subependymal giant cell astrocytomas [SEGAs], seizures, intellectual disability / developmental delay, psychiatric illness); kidney (angiomyolipomas, cysts, renal cell carcinomas); heart (rhabdomyomas, arrhythmias); and lungs (lymphangioleiomyomatosis [LAM], multifocal micronodular pneumonocyte hyperplasia). Central nervous system tumors are the leading cause of morbidity and mortality; renal disease is the second leading cause of early death. [from GeneReviews]

Tuberous sclerosis complex (TSC) involves abnormalities of the skin (hypomelanotic macules, confetti skin lesions, facial angiofibromas, shagreen patches, fibrous cephalic plaques, ungual fibromas); brain (subependymal nodules, cortical tubers, and subependymal giant cell astrocytomas [SEGAs], seizures, intellectual disability / developmental delay, psychiatric illness); kidney (angiomyolipomas, cysts, renal cell carcinomas); heart (rhabdomyomas, arrhythmias); and lungs (lymphangioleiomyomatosis [LAM], multifocal micronodular pneumonocyte hyperplasia). Central nervous system tumors are the leading cause of morbidity and mortality; renal disease is the second leading cause of early death. [from GeneReviews]

A rare soft tissue tumor characterized by distinctive perivascular epitheloid cells, often arranged radially around a vascular lumen, as well as spindled cells in variable proportion. Melanocytic and muscle markers are typically positive. The tumors have been reported in the uterus, falciform ligament, and large and small intestine, among others. Depending on their location, they may present as a painful or painless mass, or with vaginal bleeding. Tumors displaying infiltrative growth, marked hypercellularity, nuclear enlargement and hyperchromasia, high mitotic activity, atypical mitotic figures, and/or coagulative necrosis should be regarded as malignant. [from ORDO]

A benign or malignant neoplasm arising from the lymphatic vessels. [from HPO]

A neoplasm with perivascular epithelioid cell differentiation, often associated with tuberous sclerosis. It is characterized by the presence of smooth muscle and epithelioid cells and by the proliferation of lymphatic vessels. Sites of involvement include the lymph nodes, lung, mediastinum, and retroperitoneum. [from NCI]

A lung tumor that arises from perivascular epithelioid cells (PECs). [from NCI]

Breast fibrocystic change characterized by the prominence of fibrotic changes in the parenchyma. [from NCI]