SUMMARY. The case is described of a 39 year-old woman with lymphangioleiomyomatosis (LAM). She was a non-smoker who was hospitalized as an emergency following sudden onset of chest pain and shortness of breath upon exertion (III/IV). Clinical examination of the respiratory tract showed reduction of respiratory sounds in the right hemithorax. Right pneumothorax was identified on the chest X-ray and chest CT scan showed: a) diffuse unilateral pneumothorax of the right lung, b) atelectasia of the right lower lobe, c) multiple lung cysts across all lung segments, d) thickening of the interstitial lung tissue of the left lower lobe and the lingual segment, e) peripheral nodules in the posterior basal lung segments, and f) left transposition of the mediastinum. This picture was consistent with the presence of LAM, based on which an open lung biopsy was performed, which confirmed the diagnosis. LAM is a rare disorder of the respiratory system which belongs to the interstitial lung diseases and can occur either in a sporadic form (S-LAM) or in association with tuberous sclerosis complex (TSC). Pneumon 2008; 21(3):–