Intra-abdominal pulmonary sequestration: diagnostic difficulties.

This case report describes the unusual occurrence of congenital cystic adenomatoid malformation (CCAM) type 2 in an intra-abdominal pulmonary sequestration as a cause of diagnostic difficulties. The mass was discovered incidentally during a routine prenatal ultrasound in an infant with no other congenital malformation. Extralobar pulmonary sequestrations (EPS) located in the abdomen are rarely diagnosed prior to excision. The presence of CCAM type 2 in this situation might impose difficulties in histologic diagnosis of EPS, especially at the time of frozen section as happened in this case. To our knowledge this case is the sixth reported case of intra-abdominal EPS and the sixteenth case of EPS histologically displaying the feature of CCAM type 2. Pathologists should be aware that EPS in any location might display histologic features of CCAM type 2 even if the EPS is intra-abdominal.