Chondroid cystic malformation of the lung with trisomy 8 mosaicism: a new cystic lung malformation.

Neonatal cystic disorders of the lungs are a heterogeneous malformative group including giant lobar hyperinflation, congenital pulmonary airway malformations, intralobar pulmonary sequestration, and bronchogenic cyst. Here, we describe a giant cystic pulmonary malformation in a 5-year-old girl, morphologically characterized by a highly disorganized proliferation of numerous cartilage islands, abundant mesenchymal tissue with abundant adipose differentiation, and epithelium-lined cysts. Cytogenetic analysis revealed an isolated trisomy 8, as the sole karyotype anomaly, a finding further confirmed by a whole-genome single nucleotide polymorphism array genotyping. The trisomy 8 was observed by fluorescent in situ hybridization within the malformation, and also in adjacent pulmonary parenchyma. A search of the literature revealed only 2 cases having similarities with the present case, but bearing different names. We believe that this lesion differs from congenital pulmonary airway malformations and from adult-type pulmonary hamartomas. We propose for this malformative mass the name "chondroid cystic malformation of the lung."