Extralobar pulmonary sequestration mimicking cystic adenomatoid malformation in prenatal sonographic appearance and histological findings

An infant girl with extralobar pulmonary sequestration (PS) composed of congenital cystic adenomatoid malformation (CCAM)-like structure is presented. Initially, the antenatal sonographic findings indicated CCAM. The macroscopic findings of the resected specimen were compatible with extralobar PS; however, the microscopic findings showed cystic structure mimicking type II CCAM. The combination of PS and CCAM is rare, and it is likely that the embryological origin is common to both. There is confusion in the classification of these two congenital anomalies. In this report, the histological and sonographic findings of PS and CCAM are discussed.