Pleuropulmonary blastoma (PPB) is a rare childhood cancer occurring in the chest, specifically in the lungs or in the coverings of the lungs called "pleura". PPB occurs almost exclusively in children under the age of approximately 7-8 years and rarely in older children, in teenagers and more rarely in adults. Three subtypes of PPB exist and are called type I, type II, and type III PPB. Type I PPB takes the form of cysts in the lungs (air-filled pockets) and occurs in the youngest children with PPB (from birth to about 2 years of age). Type II PPB has cysts and solid tumor. Type III PPB is entirely solid tumor. Types II and III PPB tend to occur after age 2 years. Children with type I PPB can have the disease come back. If type I PPB comes back, it usually happens within about 4 years of the original diagnosis, and it is usually type II or III when it recurs. Children with type I PPB have a better outlook ("prognosis") than children with types II and III PPB; most type I PPB patients are cured (more than 80%). Treatment for type I consists of surgery and possibly chemotherapy; for Types II and III PPB surgery, chemotherapy and possibly radiation therapy is recommended. At present, about 50-60% of types II and III children are cured.
What kind of cancer is PPB? PPB is a childhood cancer in the family of cancers called "soft tissue cancers", which are scientifically called "sarcomas". PPB is, therefore, a "soft tissue sarcoma". PPB is related to, or in the broad family of, cancers such as cancers of muscle, cartilage, and connective tissues. Physicians classify diseases this way in order to compare features and to compare treatments. Often treatments that are effective for one member of a family of cancers are effective for other members of that family.
PPB occurs in the lungs so PPB can be called a "lung cancer". But PPB has no connection whatsoever with lung cancers in adults that are often related to tobacco use.
Can PPB spread to other parts of the body? Like many cancers, PPB can spread through the blood to other areas of the body. When a cancer spreads to another part of the body it is called a "metastasis" of the cancer. Types II and III PPB can metastasize. The most common location for a PPB metastasis is the brain. It can also spread to the bones, the liver, and remaining parts of the lung. It is not known why PPB has this pattern of spread to brain, liver, or bones. PPB can also spread by growing directly into tissues next to the lung like the diaphragm.
PPB family cancer syndrome: In about 25% of children with PPB, there are other childhood cancers or abnormalities in the PPB patient or in their families. This is called the PPB family cancer syndrome. This can include lung cysts, kidney cysts, thyroid tumors (sometimes malignant), and various other cancers. It is not known what causes the abnormalities in these children and families, but research is underway to discover the presumed genetic basis for this tendency to childhood cancers or other abnormalities. It should be emphasized that many children and adults in these families have no medical problems.