[The Proteus syndrome: a rare cause of pulmonary emphysema]

The Proteus syndrome is a rare genetic disease which is characterized by the overgrowth of tissues, especially bone, connective and adipose tissue. This condition is related to a somatic mosaic activating mutation in the AKT1 oncogene.

We report the case of a 25-year-old man, diagnosed with the Proteus syndrome at the age of 6 months. He exhibited an asymmetric overgrowth of the extremities leading to bilateral amputation of the legs at the age of 10 years. He was hospitalized for acute respiratory failure due to a bronchopulmonary infection. Severe bullous pulmonary emphysema, predominantly on the left, with mediastinal deviation, was diagnosed. The patient recovered with antibiotics. An assessment 2 months later revealed mild hypoxaemia (PaO2=75 mmHg) and severe airflow limitation (FEV1=1260 mL [28% th.], FEV1/V C=69%) with hyperinflation (TLC=7840 mL [107% th.], RV=6010 mL [253% th.]).

The Proteus syndrome is a very rare cause of pulmonary emphysema. The pathophysiology of emphysema in this syndrome is unknown. It can be hypothesized that the development of pulmonary cysts leading to emphysema may share the same AKT1 activation pathway with lymphangioleiomyomatosis.