Purpose or Case Report:
Pleuropulmonary blastoma (PPB) is a rare, intrathoracic, malignant tumor in the pediatric population with approximately 500 cases reported worldwide. Over 90% of these cases are in patients below the age of 6. The spectral morphology of PPB is used to classify the lesions along a continuum from the least malignant to the most malignant: type I (cystic) 14%, type II (solid and cystic) 48%, and type III (solid) 38%. Congenital lung cysts are not known to degenerate to become PPB, but the cystic type I PPB may progress to the more aggressive type II or type III PPB. In addition, PPB is associated with cystic nephroma in 30% of cases, and has been linked to the DICER1 mutation which puts these patients at risk for other tumors. For example, the genetic basis of the PPB familial syndrome (which is the heterozygous loss of function mutation of DICER1) includes PPB, cystic nephroma, ovarian Sertoli-Leydig cell tumors, ciliary body medulloepithelioma, nodular hyperplasia and differentiated carcinoma of the thyroid gland, pituitary blastoma, pineoblastoma, nasal chondromesenchymal hamartoma, and cervical embryonal rhabdomyosarcoma.
The purpose of this educational report is to demonstrate various presentations and identify distinguishing features of each type of PPB as seen on initial radiographs with correlation on subsequent CT scans. Only cases where the PPB and type were confirmed by pathology are included. At least one case of the PPB familial syndrome will also be presented. Positive DICER1 mutations will be provided when available, as this information is increasingly used to aid in the treatment decisions. Early recognition of PPB with timely investigation for cystic nephroma and DICER1 mutations can lead to improved patient outcomes.
Methods & Materials:
Results:
Conclusions: