The lungs in lymphangiomyomatosis and in tuberous sclerosis.

Two cases of pulmonary lymphangiomyomatosis (PL) are described and 33 other cases from the literature are reviewed. These are compared with one case of tuberous sclerosis with pulmonary involvement (PTS) and 32 other cases from the literature. There are no differences in lung function between these two conditions, both of which show airways obstruction associated with diffuse radiological lung changes. There are, however, both clinical and radiological differences and also differences in the distribution of the lesions and the histological location of the excessive smooth muscle; these indicate that PL and PTS are probably different entities and not polar forms of one condition. Finally, the strictly female incidence of PL suggests a sex-linked disorder, and it is postulated that this may be related to congenital pulmonary lymphangiectases.