Lymphangiomyomatosis

Lymphangiomyomatosis occurs only in women, usually of child-bearing age. The majority present with dyspnoea. Sixty per cent develop chylous pleural effusions, and 40% develop pneumothorax. Identical clinical, radiological and pathological pulmonary changes may be seen in about 1% of patients with tuberous sclerosis. Although tuberous sclerosis affects both sexes equally, the pulmonary changes have been described almost exclusively in women. Almost all patients die within 10 years of the onset of symptoms. Recently, improved prognosis has been reported following treatment with progesterone or oophorectomy.

The plain radiological manifestations of LAM include reticular, reticulonodular, miliary and honeycomb patterns. Lung volumes can be increased in patients with this disease. On HRCT, patients with LAM characteristically show numerous thin-walled lung cysts, surrounded by relatively normal lung parenchyma (Fig.1). These cysts usually range from 2 mm to 5 cm in diameter, but can be larger. Their size tends to increase with progression of the disease. In the majority of patients the cysts are distributed diffusely throughout the lungs, and no lung zone is spared; diffuse lung involvement is seen even in patients with mild disease. In some cases, a slight increase in linear interstitial markings, interlobular septal thickening, or patchy areas of ground glass opacity are also seen. Other features of LAM that can be seen on CT include hilar, mediastinal, and retrocrural adenopathy. Pleural effusion can also be seen, and can be helpful in distinguishing LAM from Langerhans cell histiocytosis.

RW