- Abnormal proliferation of interstitial smooth muscle cells, which obstruct small airways, causing air trapping and the formation of numerous thin-walled cysts.
- The smooth muscle cell proliferation also causes lymphatic obstruction, which in turn may cause chylous fluid collections.
- Exclusively affects women of child bearing age.
- LAM is nearly identical to tuberous sclerosis-associated lung disease; however, intelligence is normal in patients with LAM.
- Features of TS like angiomyolipoma of kidney and subependymal nodules can also be seen in LAM.
- Radiographic features
– In contrast to Langerhans cell histiocytosis, which has an upper lobe predominance, cysts in LAM are uniformly distributed, without sparing of costophrenic angle.
– Cysts in LAM are also more regular in shape.
- Other cystic lung diseases
– TS-associated lung disease
- Treatment: despite treatment with agents such as medroxyprogesterone and tamoxifen, LAM tends to be progressive with most of disease severity due to pulmonary disease.