Pleuropulmonary blastomas (PPB) are rare, variably aggressive, childhood primary intrathoracic malignancy. In up to 25% of cases, the mass can be extrapulmonary with attachment to the parietal pleura.
PPB is encountered in childhood, mostly in the first years of life (90% in those between 0-2 years old).
PPB comprises of mesenchymal and epithelial components resembling fetal lung. Bilateral occurrence is very rare.
This classification is a continuum from the less malignant to the most malignant lesion:
- cystic: type I (prenatal and 10 months old), 14%
- mixed: type II (mean age 34 months), 48%
- solid: type III (mean age 44 months), 38%
Type 1 PPBs are impossible to differentiate from types 1 and 4 CPAM. Thus, it must be included in the differential diagnosis, particularly if the patient is known for another type of blastoma, as 25% of PPB appear in families with history of blastomas.
PPBs are usually right sided, pleural bases, without chest wall invasion and without calcifications. It can sometime present with pneumothorax. Types 2 and 3 PPBs are associated with CNS and bone metastases.
PPBs are associated with type 4 CPAM.
PPB is associated with PPB family tumour and dysplasia syndrome in 33% of cases. Many of these patients have a mutation of the DICER-1 gene. In 10% of cases, patient with PPB may also present with multilocular cystic nephroma, and, very rarely, Wilms tumour 7-9.
Often late presentation at radiographic diagnosis. Unilateral lung whiteout on plain film with mediastinal shift to opposite side. Usually there is no adjacent rib erosions or calcification.
Usually seen as a large mass in the thorax with solid mixed cystic heterogeneous low attenuation, pleural effusion (not dominant abnomality), contralateral mediastinal shift, and lack of chest wall invasion 3-4.
Not good imaging modality of choice. Non specific and may shows a large region of consolidation without sonographic air bronchograms 3.
Treatment and prognosis
Type I tumours have a good prognosis. Complete surgical resection is often the treatment of choice, as it is with CPAM. Tumors larger than 5 cm just like type 1 and 2 PPB carry a worse prognosis 2.
General imaging differential considerations include:
- intrathoracic soft tissue sarcoma
- PNET of thorax
- large bronchogenic cyst/lung cyst (for type I)
- FLIT (fetal lung interstitial tumour)10
- types 1 and 4 CPAM's: for type 1 PPB
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- 7. Hill DA, Ivanovich J, Priest JR et-al. DICER1 mutations in familial pleuropulmonary blastoma. Science. 2009;325 (5943): 965. doi:10.1126/science.1174334 - Free text at pubmed - Pubmed citation
- 8. Foulkes WD, Bahubeshi A, Hamel N et-al. Extending the phenotypes associated with DICER1 mutations. Hum. Mutat. 2011;32 (12): 1381-4. doi:10.1002/humu.21600 - Pubmed citation
- 9. Bahubeshi A, Bal N, Rio frio T et-al. Germline DICER1 mutations and familial cystic nephroma. J. Med. Genet. 2010;47 (12): 863-6. doi:10.1136/jmg.2010.081216 - Pubmed citation
- 10. Hammoudeh M, Alarfaj A, Chen DY et-al. Safety of tumor necrosis factor inhibitors use for rheumatoid arthritis and ankylosing spondylitis in Africa, the Middle East, and Asia: focus on severe infections and tuberculosis. Clin. Rheumatol.;: 1-8. Clin. Rheumatol. (full text) - doi:10.1007/s10067-012-2137-7 - Pubmed citation
- 11. Priest JR, Williams GM, Hill DA et-al. Pulmonary cysts in early childhood and the risk of malignancy. Pediatr. Pulmonol. 2009;44 (1): 14-30. doi:10.1002/ppul.20917 - Pubmed citation
- 12. Sarangi PK, Sagar HS, Nahak SK, Mohanty J, Parida S. Case report Bilateral pleuropulmonary blastoma (PPB) in a 2-year-old girl: A case report with review of literature. Journal of Medical and Allied Sciences. 2017;7(1):67-71. doi:https://doi.org/10.5455/jmas.252500
lung cancer: overview
non-small cell lung cancer
- adenosquamous carcinoma
- large cell carcinoma
- primary sarcomatoid carcinoma of lung
- squamous cell carcinoma
- salivary gland type tumours
- pulmonary neuroendocrine tumours
- preinvasive lesions
- benign neoplasms
- pulmonary metastases
- lung cancer screening
- lung cancer staging
- non-small cell lung cancer