Lymphangioleiomyomatosis: a review of the literature.

Lymphangioleiomyomatosis (LAM), characterized by alveolar smooth muscle proliferation and cystic destruction of lung parenchyma, can occur as a rare sporadic disease or as a complication of tuberous sclerosis (TSC). It is a cystic lung disease, usually generalized and progressive, may be extremely difficult to treat and has been considered to have a poor prognosis. It has almost exclusively been reported to present in women of childbearing age, most commonly with dyspnoea and pneumothorax. We reviewed the English literature from 1939 to 1997 for cases of LAM both with and without TSC, in order to document the prevalence, clinical features, investigations, treatment and outcome within and between these two groups. No study has yet determined the prevalence of LAM symptomatically within the general population, but it probably affects 1-3% of the TSC population. Patients with TSC often present with an insidious onset of dyspnoea whilst non-TSC patients present more commonly with acute breathlessness secondary to pneumothorax. Patients with TSC are also less likely to suffer from chylothorax. The age of onset of symptoms and of diagnosis are similar. LAM is rare in children and even less common in males in both groups. The natural course of LAM remains unclear and effect of treatment variable. Although symptomatic LAM is uncommon it causes a significant amount of morbidity and mortality both in the TSC and general population, but asymptomatic LAM is not uncommon in TSC. Further research is required to determine the natural history of this condition and to evaluate current treatment regimes.