Lymphangioleiomyomatosis (LAM) is a rare multi-system disorder that can occur either sporadically or in association with the tuberous sclerosis complex (TSC) and is often considered a forme fruste of TSC.
It almost exclusively affects women of child-bearing age 7. The estimated incidence is 1:400,000 4.
The disease is characterised by the persistence of dilated lymphatics and interstitial proliferation of abnormal smooth muscle that in turn can obstruct venules, lymphatics, and small airways.
In the chest, there are two phases of proliferation in lymphangioleiomyomatosis. The early phase is characterised by proliferation of immature muscle cells that cover alveolar walls, bronchioles, pleura and vessels, including lymphatic routes. In the late phase there is a development of cystic spaces and wider proliferation of muscle cells throughout the lung.
Lymphangioleiomyomatosis is a multi-system disorder and can affect many organs.
May show massive osteolysis with little or no periosteal reaction. Often multifocal disease
Multiple thin walled cysts throughout the lungs (usually with a uniform distribution). These are present in nearly all cases. If the cysts are small, they may be seen as diffuse coarse interstitial markings on plain film.
- thin walled cysts of variable sizes surrounded by normal lung parenchyma can be seen throughout the lung
- interlobular septal thickening
- may show a dilated thoracic duct
- haemorrhages may be seen as areas of increased attenuation
Abdomen and pelvis
- renal angiomyolipomas: most common abdominal finding 2,3
- splenic cysts
- chylous ascites
- uterine fibroids 2
- abdominal lymphadenopathy 3
- recurrent pneumothorax can occur in up to 80% of cases
- thoracic chylous collections
- haemoptysis (occasional) 4
- pelvic lymphatic obstruction
Treatment and prognosis
Despite treatment with agents such as medroxyprogesterone and tamoxifen 6, LAM tends to be progressive with most of disease severity due to pulmonary disease.
For pulmonary manifestations, the primary differential to be considered is:
Langerhans cell histiocytosis (LCH)
- tends to happen in children and young adults with a history of heavy cigarette smoking
- mid to upper lobe distribution with preservation of costophrenic angle.
- cysts in LCH tend to be more irregular in contour
- has much more favourable prognosis compared with LAM
- 1. Aberle DR, Hansell DM, Brown K et-al. Lymphangiomyomatosis: CT, chest radiographic, and functional correlations. Radiology. 1990;176 (2): 381-7. Radiology (abstract) - Pubmed citation
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- 4. Johnson SR, Cordier JF, Lazor R et-al. European Respiratory Society guidelines for the diagnosis and management of lymphangioleiomyomatosis. Eur. Respir. J. 2010;35 (1): 14-26. doi:10.1183/09031936.00076209 - Pubmed citation
- 5. Sundaram B, Gross BH, Martinez FJ et-al. Accuracy of high-resolution CT in the diagnosis of diffuse lung disease: effect of predominance and distribution of findings. AJR Am J Roentgenol. 2008;191 (4): 1032-9. doi:10.2214/AJR.07.3177 - Pubmed citation
- 6. Oh YM, Mo EK, Jang SH et-al. Pulmonary lymphangioleiomyomatosis in Korea. Thorax. 1999;54 (7): 618-21. Thorax (link) - Free text at pubmed - Pubmed citation
- 7. Abbott GF, Rosado-de-christenson ML, Frazier AA et-al. From the archives of the AFIP: lymphangioleiomyomatosis: radiologic-pathologic correlation. Radiographics. 25 (3): 803-28. doi:10.1148/rg.253055006 - Pubmed citation