Bound to Become Breathless: A Case Report on Lymphangioleiomyomatosis (LAM)

摘要

Abstract Introduction: Lymphangioleiomyomatosis (LAM) is a rare progressive cystic lung disease predominantly affecting women. It most commonly presents as dyspnea during exercise but can be noted incidentally on imaging performed for other concerns. We present a case report of a patient with LAM suggested incidentally by CT scan findings who later presented with spontaneous pneumothorax. Description: A 46-year-old woman presented with progressive dyspnea and substernal chest pain for 3 days. There was no fever, diaphoresis, recent travel, immobilization, or trauma. She had a history of cystic lung disease which was incidentally diagnosed three years prior when she underwent imaging studies of her abdomen. She was a never-smoker and had no occupational or environmental risk factors. On examination, she had decreased breath sounds in the left lung fields with hyper-resonance on percussion. Chest imaging showed a left-sided pneumothorax. Multiple thin-walled diffuse cysts suggestive of LAM were also noted which were similar in appearance to three years prior. A left-sided intercostal chest tube was placed which resulted in the resolution of the pneumothorax. Cardiothoracic surgery was consulted, and she underwent robotic left upper lobe wedge resection, pleurectomy, and mechanical pleurodesis. Histopathology of the surgical lung biopsy sample revealed intraparenchymal cyst formation with smooth muscle-like LAM cells in clusters with human melanoma black (HMB)-45 immunoreactivity which was definitively diagnostic for LAM. The patient gradually recovered after surgery and was discharged from the hospital a few days later. She is being regularly monitored with computed tomography (CT) scans, and pulmonary function tests and has been referred to a LAM foundation clinic for further specialized care. Discussion: LAM is seen almost exclusively in women and can occur in the setting of tuberous sclerosis complex (TSC) or may be sporadic with an incidence of 5 per 1 million women. Careful review of radiologic features is critical to diagnosis with differentials including Birt-Hogg-Dube syndrome, Langerhans cell histiocytosis, and lymphoid interstitial pneumonia. Diagnosis can be confidently established in patients with compatible history and radiological findings with TSC, renal angiomyolipomas, serum VEGF-D greater than 800 pg/mL, chylous effusions, or lymphangioleiomyomas. Demonstration of LAM cells with HMB-45 immunoreactivity is the gold standard for diagnosis. Sirolimus, the only FDA-approved medication and the first-line treatment for LAM, is recommended only in patients with abnormal lung function. Patients with LAM are at a high (70%) risk of developing recurrent spontaneous pneumothoraces. Pleurodesis should be offered following the first episode of spontaneous pneumothorax.