Cystic Lung Disease in a Patient With Proteus Syndrome

Abstract

Introduction: Proteus Syndrome is a rare disfiguring disease due to an AKT1 mutation. It is defined by cerebriform connective tissue, epidermal nevi, disproportionate overgrowth of limbs and bones, lipomas and may manifest with cystic lung disease. CASE PRESENTATION: This is a case of a 24 year old man with Proteus Syndrome who was referred for dyspnea. The patient was diagnosed in infancy when he displayed classic physical findings. In 2008 he had progressive orthopnea, dyspnea with exertion and a dry cough. At his initial clinic visit, room air saturation was 93%, PFTs demonstrated obstruction (FEV1/FVC 37%), hyperinflation, and reduced diffusion. A chest CT had severe cystic disease of the right lung with hyperinflation and mediastinal shift. Shortly after he was oxygen dependent. In 2014 he came to the ER with hemoptysis and abdominal distention. CT abdomen showed massive splenomegaly and a splenic embolization was planned. Arterial blood gas showed an acute respiratory acidosis with PaCO2 ranging 60-90mmHg. Transthoracic echo was notable for severe pulmonary hypertension with right ventricular overload and inhaled nitric oxide was given. Despite noninvasive ventilation, he remained hypoxic and hypercapneic, suffered a PEA arrest, and expired shortly thereafter. DISCUSSION: Pulmonary complications of Proteus Syndrome can be life threatening. Chest wall deformity occurs from massive rib overgrowth, scoliosis or megaspondylodysplasia. Enlarged, irregular cysts occur with centrilobular emphysema. Excessive growth of bullae results in lateral displacement of the mediastinum and compression of the opposite lung. Those with localized emphysema may benefit from early lung reduction surgery. CT densitovolumetry should be done to quantify the extent of the lung disease to help predict respiratory failure. Conclusions: This case demonstrates profound cystic disease due to Proteus Syndrome. The mechanism of cysts and emphysema is unknown and may develop early in childhood and go unrecognized and untreated. Respiratory failure is likely the cause of premature death. Surgery is often not an option and the role of transplant is unclear.