Lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare disease of the lungs and lymphatics, which can occur sporadically or in association with tuberous sclerosis. LAM almost exclusively affects females, generally developing before the menopause. The disease is characterised by progressive pulmonary cystic change, recurrent pneumothorax, chylous pleural collections and, in most cases, progressive respiratory failure. Abdominal manifestations include lymphadenopathy, cystic lymphatic masses (lymphangioleiomyomas), chylous ascites and angiomyolipoma (a benign tumour). Survival in LAM is approximately 70% at 10 yrs, although this is highly variable since long-term survivors have been described. Diagnosis is made by a combination of clinical features and computed tomography scanning or, in cases of doubt, lung biopsy. In patients with rapidly progressive disease, hormone treatment (predominantly progesterone) has been used, although no firm evidence supports its use. Otherwise, treatment is aimed at complications including pneumothorax, chylous collections and extrapulmonary manifestations. The only treatment for severe LAM is currently lung transplantation. Recent developments in the cell biology of lymphangioleiomyomatosis have shown that these patients have somatic mutations in the genes linked to tuberous sclerosis and that rapamycin may correct the resulting cellular abnormality. Trials of rapamycin in lymphangioleiomyomatosis are currently underway and offer hope of evidence-based treatment for the disease.