Unusual signal intensity of congenital pulmonary airway malformation on fetal magnetic resonance imaging

Abstract

Congenital pulmonary airway malformation (CPAM) is classified into pathologically different types. These types are sometimes distinguishable by fetal lung MRI and are usually observed as higher-signal lesions on T2-weighted images than normal lung. We describe a case of unusual CPAM resembling neoplasms, with a lower signal than is found in normal lung. Histopathology showed a large number of mucogenic cells but found no evidence that could explain this feature on fetal MRI. An unusual low-signal mass associated with a pulmonary cyst in fetal lung on MRI may suggest an unusual type 1 CPAM.

Magnetic resonance imaging for congenital lung malformations

“…Other lesions might mimic or need to be differentiated from bronchopulmonary malformations, both pre-and postnatally. Bronchopulmonary malformations generally have a typical imaging appearances prenatally (T2-weighted hyperintense signal with or without small or large cysts, systemic vessels, mucoid impaction) [15,20]. Other chest and mediastinal masses including diaphragmatic hernia and neurogenic and vascular lesions are usually readily distinguished from bronchopulmonary malformations on imaging.…”

“…Solid neoplastic lesions such as infantile fibrosarcoma and peribronchial myofibroblastic tumor and chest wall mesenchymal hamartoma are usually different in their imaging appearance as compared to bronchopulmonary malformations (more heterogeneous, can be iso-to hypointense on T2-weighted images). Occasionally bronchopulmonary malformations have an atypical appearance with T2-weighted hypointensity, possibly caused by myxoid or immature highly cellular mesenchymal components [9,[20][21][22]. Fetal lung interstitial tumor is a rare benign lesion that is uniformly T2weighted hyperintense on MR [9].…”