Supplementary Material for: Fetal Bronchoscopy as a Useful Procedure in a Case with Prenatal Diagnosis of Congenital Microcystic Adenomatoid Malformation R.Cruz-Martinez A.Méndez O.Perez-Garcilita A.Monroy K.Aguilar-Vidales M.A.Cruz-Martinez C.Martinez-Morales 2014 Massive microcystic congenital cystic adenomatoid malformation (CCAM) and bronchial atresia are associated with a high perinatal mortality secondary to lung hypoplasia and cardiac dysfunction, and fetal intervention should be considered to improve prognosis. Therapeutic options include open fetal surgery with pulmonary resection, fetal sclerotherapy and fetoscopy. We present a case with a severely enlarged left lung without ultrasound signs of dilated airways compatible with the diagnosis of microcystic CCAM, hydrops and severe contralateral lung hypoplasia that was treated successfully at 30 weeks of gestation by fetal bronchoscopy, through which bronchial atresia was identified at the end of the left mainstem bronchi and permeabilized by laser ablation. After fetal surgery, weekly follow-up showed a progressive decrease in the affected lung size and an increase in the contralateral hypoplastic lung size, demonstrating normal dimensions of both lungs at 34 weeks of gestation, reversal of the mediastinal shift, and complete disappearance of hydrops. A healthy neonate was delivered uneventfully at term with no need for respiratory support, and the boy is now doing well at 15 months of age. This report demonstrates that in cases with prenatal diagnosis of large microcystic CCAM, fetal bronchoscopy can be used to refine the diagnosis of bronchial atresia and as a therapeutic tool with good outcome.