Fetal MRI of Torsed Bronchopulmonary Sequestration with Tension Hydrothorax and Hydrops in a Twin Gestation.

While bronchopulmonary sequestration typically has a benign course, this congenital lung malformation has a high mortality rate when associated with untreated in utero tension hydrothorax and hydrops. Hydrops related to bronchopulmonary sequestration is believed to result from torsion of the mass with compromise of the associated blood supply. The impaired venous return of the mass then leads to tension hydrothorax with compression of the heart and mediastinal vessels, impairing global venous return. To our knowledge, this scenario has only been described prenatally by ultrasound. We present the imaging findings of a dichorionic, diamniotic twin gestation with one fetus developing tension hydrothorax and hydrops from presumed intermittent torsion of a bronchopulmonary sequestration. This diagnosis was only able to be confirmed by MRI prior to the use of ultrasound-guided interstitial laser photocoagulation for the treatment of this anomaly.