IS Case 16: Lymphangiomyomatosis
Imaging Sciences URMC 2008
Publication Date: 2009-05-18
Plain chest radiographs often demonstrate increased interstitial markings in a reticular pattern. It is difficult to appreciate the cysts due to their nearly imperceptible thin walls. CT demonstrates extensive replacement of the lung parenchyma with thin walled cysts.
Lymphangiomyomatosis (LAM) is a rare disease characterized by progressive proliferation of atypical smooth muscle in the walls of the bronchi, bronchioles, alveolar septa, pulmonary vessels, lymphatic vessels, and pleura. The proliferation of the atypical muscle cells leads to air trapping and the development of emphysema and cystic air spaces. The parenchymal changes are progressive, eventually leading to diffuse honeycomb appearance with increased lung volumes. It is associated with young females of child-bearing age who are usually between 17 to 50 years of age which suggests that estrogen plays a role in the pathogenesis.
Identical clinical, radiologic, and pathologic pulmonary changes may be seen in 1% of patients with tuberous sclerosis. Although tuberous sclerosis affects both females and males, the pulmonary changes are described exclusively in women.
On chest radiographs, the pulmonary parenchymal changes may be seen as reticular, reticulonodular, military or honeycombing patterns. Other findings include pneumothorax and chylous pleural effusion secondary to involvement of the thoracic duct. On CT, LAM is characterized by bilateral diffuse and extensive cystic air spaces. In mild disease, the spaces measure less than 0.5 cm and those with more extensive disease, the cysts are greater than 1 cm. The cystic walls range from faintly perceptible to 2 mm thick and are surrounded by normal parenchyma.
- Muller NL, Chiles C, Kullnig P. Pulmonary lymphangiomyomatosis: correlation of CT with radiographic and functional findings. Radiology. 1990 May;175(2):335-9. [PMID: 2326457]
- Bonelli FS, Hartman TE, Swensen SJ, Sherrick A. Accuracy of high-resolution CT in diagnosing lung diseases. AJR Am J Roentgenol. 1998 Jun;170(6):1507-12. [PMID: 9609163]