This is a rare disorder caused by smooth muscle proliferation of unknown etiology in the airways, pulmonary vessels and lymphatics. This disorder may be confined to the lungs, or the thoracic duct and lymph nodes in the thorax and retroperitoneum may also be involved. This disorder is seen exclusively in women usually during their child-bearing years and persons afflicted with tuberous sclerosis. The disease course is usually progressive and eventually leads to respiratory failure and death. The differential diagnosis should include idiopathic interstitial pneumonitis, sarcoidosis, eosinophilic granuloma and pulmonary hemosiderosis.

This disease manifests clinically as dyspnea with an associated cough. Pleural effusion, hemoptysis (which may be life-threatening), and spontaneous pneumothorax comprise the triad of symptoms commonly associated with this disorder. A chylous effusion is noted on analysis of the pleural fluid with a pleural fluid triglyceride content that is always greater than 100 mg/dL and frequently greater than 400 mg/dL. Vascular endothelial growth factor-D (VGEF-D) levels are markedly elevated usually to levels greater than 800 pg.mL.

Radiographic findings include hyperinflation and honeycombing. Abnormalities noted on computed tomography include interstitial thickening, cystic lesions and hilar or mediastinal lymph nodes. High resolution CT scanning is a reliable noninvasive means of establishing the diagnosis. Pulmonary function testing shows an obstructive pattern and a severely reduced DLCO. Early in the disease course hypocapnia is noted on arterial blood gas sampling; however, as the disease progresses, hypercapnia is often noted. Chyluria is a strongly suggestive finding and should prompt an aggressive attempt to establish the diagnosis. A definitive diagnosis is established by transbronchial or open lung biopsy. Biopsy specimens are characterized pathologically by the presence of nodular and tortuous masses of smooth muscle cells without the presence of fibrosis.

The severity of disease may increase with pregnancy or estrogen therapy and may remit with the onset of menopause. Therapy for disease may include progesterone or tamoxifen, or surgical intervention in the form of oophorectomy or heart-lung transplantation may be required. Because heart-lung transplantation is a potential therapy, transbronchial biopsy may be preferable to open lung biopsy in order to avoid thoracic incisions prior to surgery. Corticosteroids, radiation therapy and antineoplastic drugs are not effective in treating this disorder and should be avoided due to the potential for side effects. If recurrent pneumothorax or symptomatic chylothorax complicate the disease, then surgical or chemical pleurodesis may be required.

Sirolimus may be a therapeutic option.  Referral to a specialist is prudent.