Intra-abdominal pulmonary sequestration exhibiting congenital cystic adenomatoid malformation. Report of a case and review of the literature.

We describe the fifth case, to our knowledge, of an intra-abdominal pulmonary sequestration that histologically displayed the features of congenital cystic adenomatoid malformation (CCAM) type 2. This mass was found during routine prenatal ultrasound in an infant with no other congenital malformations. A literature search found 13 previously reported cases of CCAM in extralobar pulmonary sequestration (EPS), nine of which were thoracic and only four were intra-abdominal. An analysis of our case and the 13 previously reported cases shows that the clinical features of EPS containing CCAM type 2 do not differ significantly from those of EPS occurring alone. The presence of CCAM type 2 in our patient is consistent with previously reported cases. Extralobar pulmonary sequestrations located in the abdomen are rarely diagnosed prior to excision, and the presence of CCAM type 2 in this situation may further compound diagnostic difficulties. The morphologic features separating CCAM into three distinct types and the exclusive association of CCAM type 2 occurring in EPS are also discussed.