Mediastinal and pleural lipomatosis as a manifestation of myotonic dystrophy type 1

Mediastinal and pleural lipomatosis is a rare but usually benign and asymptomatic disease. Mediastinal lipomatosis is associated with steroid use, obesity, hyperlipidemia, diabetes, or Cushing syndrome. In some cases, it becomes symptomatic manifesting with dyspnea, thoracic pain, coughing, dysphonia, dysphagia, supraventricular tachycardia, or persistent pneumonia. Mediastinal lipomatosis has not been reported in association with myotonic dystrophy type 1 (MD1). In a 65yo male with a long-term history of progressive muscle weakness, hyper-creatine-kinase-emia, bilateral cataract, sleep apnea syndrome, gynecomastia, hepatic steatosis, arterial hypertension, atrioventricular block 1, QTc prolongation, hyperlipidemia, hyperuricemia, and hepatopathy, MD1 was diagnosed upon the clinical presentation and a heterozygous CTG repeat expansion of 1200-1400 repeats in DMPK. Work-up for dyspnea and leg edema revealed heart failure and mediastinal and pleural lipomatosis. Upon standard treatment, heart failure resolved. In conclusion, mediastinal and pleural lipomatosis can be a rare manifestation of MD1 and can manifest with heart failure. In patients with mediastinal lipomatosis, MD1 should be excluded.