Pleuropulmonary blastomas
Pleuropulmonary blastomas (PPB) are rare childhood cancers primarily affecting the lungs, typically diagnosed in children under the age of eight. This condition is associated with a familial history of childhood cancers and is linked to genetic syndromes, such as DICER1 syndrome, which accounts for about 40% of cases. The tumors can present as cystic formations within the lungs, and patients may experience symptoms like respiratory distress, cough, and chest pain. PPB is classified into three subtypes: Type I is generally less aggressive, while Types II and III are more severe and have a higher potential for metastasis, often spreading within or beyond the chest cavity. Diagnosis often occurs between seven to eleven months for Type I, while cerebral metastasis is more common in PPB than in other pediatric sarcomas. Treatment often involves surgery, chemotherapy, and, in some cases, radiation, with targeted therapies improving patient outcomes significantly. While the prognosis for Type I is favorable, with survival rates between 91 and 98%, Types II and III have lower survival rates, ranging from 37 to 70%, and demonstrate a poor prognosis upon recurrence.
On this Page
Subject Terms
Pleuropulmonary blastomas
ALSO KNOWN AS: Pneumoblastomas, mesenchymal cystic hamartomas, pulmonary rhabdomyosarcomas
RELATED CONDITIONS: Cystic nephromas, renal tumors
DEFINITION: Pleuropulmonary blastomas are rare childhood cancers, occurring most commonly in the lungs.
Risk factors: A risk factor for pleuropulmonary blastoma is a familial history of childhood cancers, including lung cysts, kidney cysts, and thyroid tumors. Although the specific genetic defect has not been elucidated, genetic forms of pleuropulmonary blastomas make up 40 percent of the cases and are called pleuropulmonary blastoma family tumor and dysplasia syndrome or DICER1 syndrome. Children with pleuropulmonary blastoma may have other types of cancers and neoplastic diseases outside the lung, such as cystic nephroma of the kidney.
Etiology and the disease process: Pleuropulmonary blastoma is almost always intrathoracic or intrapulmonary. Multiloculated or unilocular lung cysts often precede the development of pleuropulmonary blastoma. In 40 percent of cases, air-filled cysts were present at diagnosis, and in 25 percent of these cases, pneumothorax occurred. Pleuropulmonary blastoma is categorized into three subtypes (I, II, III), and the latter two are aggressive malignancies with metastatic potential. Metastases to contralateral or ipsilateral lung tissue develop relatively frequently. Types II and III pleuropulmonary blastoma may metastasize within or beyond the chest cavity. Metastasis in most pleuropulmonary blastoma cases occurs between 11.5 and twenty-four months after diagnosis.
Incidence: Pleuropulmonary blastoma is a rare condition that occurs almost exclusively in children under the age of seven to eight years. Type I disease is found more often in younger children and type III in older children. Pleuropulmonary blastoma accounts for 0.5 to 1 percent of all primary malignant lung tumors.
Symptoms: Symptoms of pleuropulmonary blastoma include mild to severe respiratory distress, dyspnea (shortness of breath), fever, cough, and chest or abdominal pain due to air-filled cysts or pneumothorax.
Screening and diagnosis: Type I pleuropulmonary blastoma is cystic in appearance, with no grossly identifiable nodular disease. Type II is cystic and has identifiable nodular disease. Type III is a nodular disease with no detectable cystic areas. The median age of diagnosing type I pleuropulmonary blastoma is between seven and eleven months. The frequency of cerebral metastasis in pleuropulmonary blastoma typically tends to be higher than in other pediatric sarcomas.
Treatment and therapy: Type I pleuropulmonary blastoma patients are treated with surgery with or without adjuvant chemotherapy. Typically, children with types II or III pleuropulmonary blastoma are treated with surgery, chemotherapy, or radiation. The advent of targeted therapies in addition to these treatments has prolonged the life of patients. Although, after reoccurrence, treatment usually progresses to palliative care.
Prognosis, prevention, and outcomes: The overall survival in type I pleuropulmonary blastoma was between 91 and 98 percent. Type I may recur and progress to type II or III, and type II may progress to type III. After recurrence, type II and III pleuropulmonary blastoma has a poor prognosis. Overall survival rates for types II and III are between 37 and 70 percent.
Bibliography
Hasleton, P. S., and Douglas B. Flieder. Spencer's Pathology of the Lung. 6th ed., Cambridge: Cambridge UP, 2013.
Manivel, J. Carlos, et al. "Pleuropulmonary Blastoma: The So-Called Pulmonary Blastoma of Childhood." Cancer, vol. 62.8, 1988, pp. 1516–526.
Messinger, Yoav H., et al. "Pleuropulmonary Blastoma: A Report on 350 Central Pathology–Confirmed Pleuropulmonary Blastoma Cases by the International Pleuropulmonary Blastoma Registry." Cancer, vol. 121, no. 2, 2015, pp. 276-285, doi.org/10.1002/cncr.29032. Accessed 29 June 2024.
Milka, Mouna. “Pleuropulmonary Blastoma - StatPearls.” NCBI, 27 Apr. 2023, www.ncbi.nlm.nih.gov/books/NBK534211. Accessed 29 June 2024.
“Rare Cancers of Childhood Treatment (PDQ®).” National Cancer Institute, 5 Apr. 2024, www.cancer.gov/types/childhood-cancers/hp/rare-childhood-cancers-pdq. Accessed 29 June 2024.
Wells, Robert G. Diagnostic Imaging of Infants and Children. New York: McGraw, 2013.
Yuh, David D., Luca A. Vricella, Stephen Yang, and John R. Doty. Johns Hopkins Textbook of Cardiothoracic Surgery. 2nd ed., New York: McGraw, 2014.