We report a case of pleuropulmonary blastoma (PPB) prenatally diagnosed at 32 weeks of gestation. The suspected diagnoses was a congenital cystic adenomatoid malformation of the lung (CCAM). The excision of the malformation was performed through a thoracotomy at 4 months of age. On pathological examination, the presence of focal stromal hypercellularity (cambium layer) in the cyst wall was consistent with both the diagnosis of type IV CCAM or grade I PPB. The presence of nodules of immature cartilage and the positivity of particular immunohistochemical staining (indicate which staining came positive) confirmed the diagnosis of grade I PPB. Pleuropulmonary blastoma is a rare malignant tumour in children, sometimes difficult to differentiate from the type IV CCAM as they share similar circumstances of diagnosis, radiological and macroscopic features. The pathological examination does not always allow to differentiate them clearly, implying the necessity of an extended medical supervision for the children carrying those border lesions. Because of the risks of malignancy and of the risks of septic complications, surgical resection during the first year of life is often advocated. Therefore, prenatal detection is essential to allow adequate early management and complete resection of these lesions.