Congenital cystic adenomatoid malformation type 2 of lung with KRAS mutation:report of a case and review of literature
SONG Run-bao
ZHENG Hong
WANG Zhao-rui
LI Ming
Abstract：Congenital cystic adenomatoid malformation (CCAM) is a rare congenital lung developmental disease. This case involves a 4-month-and-3-day-old infant, in whom a left lung lesion was detected during prenatal examination at 30 weeks of gestation. After birth, CT examination revealed multiple air-filled areas without pulmonary markings in the lower lobe of the left lung. Gross examination showed a multilocular cystic lesion measuring 3.4 cm × 1.5 cm, with cyst diameters ranging from 0.3 cm to 1.6 cm, and smooth inner walls. Microscopic examination revealed hyperplastic, irregular cystic spaces with an adenomatous appearance. Larger cysts were lined by ciliated columnar epithelium, while smaller cysts were lined by simple cuboidal epithelium. No obvious mucous cells were observed, but small foci showed clusters of epithelial cells with possible mucinous differentiation. Immunohistochemistry showed positivity for TTF1 and CK7 in epithelial cells, and negativity for p40 and p63, with Ki-67 expression approximately 2%. qRT-PCR detected a mutation at the KRAS G12D gene locus. The child recovered well after one year of postoperative follow-up.
Keywords：Congenital Cystic Adenomatoid MalformationStocker classificationKRAS gene
Publication Date：2025-06-28
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：3( 759-760,后插1 )