Lymphangioleiomyomatosis. Physiologic pathologic radiologic correlations

Lymphangioleiomyomatosis (LAM) is a rare disease of women of child-bearing age in which there is hyperplasia of atypical smooth muscle along lymphatics in the lung, thorax, and abdomen. Among our 6 patients, 2 had recurrent pneumothorax, lymphangioleiomyomatosis being discovered during parietal pleurectomy. The other 4 underwent biopsy because of progressive dyspnea. Subsequent manifestations included 25 pneumothoraces in 4, hemoptysis in 3, and chylothorax and a retroperitoneal hemorrhage in 1 each. Corticosteroid and immunosuppressive therapy were ineffective. Four died after 2 to 11 years, and 2 are living 1 and 8 years later. Although roentgenograms of the chest initially were normal in 4, lung biopsy of 2 showed advanced disease. Eventually, all showed a paradoxic picture of an enlarging lung volume with a reticulonodular pattern and cystlike spaces. Physiologic alterations were also unique. Spirometrically determined lung volumes were normal or decreased, whereas radiographically and plethysmographically determined total lung capacity were greatly enlarged, suggesting severe air trapping. Obstructive disease was confirmed by means of forced expiratory flow in the middle half of the forced vital capacity of 24 per cent. In lymphangioleiomyomatosis, the mean single-breath diffusing capacity was only 33.2 per cent and the mean total lung capacity, 96.3 per cent, whereas in 229 patients with interstitial disease, there was a good correlation between the single-breath diffusing capacity and total lung capacity (r = 0.57, P < 0.01). Histologic findings of uneven obstruction by lymphangioleiomyomatosis of bronchioles, lymphatics, and small pulmonary veins explained the unusual radiologic and physiologic findings. Progressive dyspnea, chylous effusions, repeated pneumothoraces, and hemoptysis in women of child-bearing age should suggest lymphangioleiomyomatosis. Airflow obstruction, disproportionately poor gas exchange, and radiographically enlarged lung despite increasingly prominent interstitial markings are virtually diagnostic.