Bronchioloalveolar carcinoma and congenital cystic adenomatoid malformation.

We report on a 42-year-old woman in whom was discovered a symptomless peripheral radiologic excavated lesion of the lung, which actually existed 3 years before. All investigations were negative. A segmentectomy was performed. Histopathologic examination proved a bronchioloalveolar carcinoma in contact with a type I congenital cystic malformation of the lung. Such a malformation can be diagnosed late in adult life. The epithelial cells of the malformation might predispose to slow proliferation and malignancy, enhanced by smoking habits.