Pleuropulmonary Blastoma - Childhood: Risk Factors

Approved by the Cancer.Net Editorial Board, 09/2023

ON THIS PAGE: You will find out more about the factors that increase the chance of developing pleuropulmonary blastoma (PPB). Use the menu to see other pages.

What are the risk factors for PPB?

A risk factor is anything that increases a person’s chance of developing a tumor. Although risk factors often influence the development of a tumor, most do not directly cause a tumor. Some people with several risk factors never develop a tumor, while others with no known risk factors do.

About 70% of people with PPB have a genetic mutation of the DICER1 RNase-IIIb gene, which is a germline mutation. Germline mutations are inherited mutations that are passed down from one generation to the next in a family. About 80% of PPB patients inherited the DICER1 RNase-IIIb mutation from a parent.

The DICER1 syndrome is also associated with other cancers, such as cystic nephroma, cervical rhabdomyosarcoma, nasal chondromesenchymal hamartoma, ovarian stromal tumors, nodular thyroid hyperplasia, ciliary body medulloepithelioma, and pineoblastoma.

Doctors are looking at ways to screen children for PPB and other cancers related to DICER1 genetic mutations. For PPB, screening guidelines will help doctors know when it’s best to use a computed tomography (CT) scan to look for possible lung cysts or tumors, particularly for children under the age of 3. Magnetic resonance imaging (MRI) of the brain for children with the DICER1 germline mutation is also being evaluated for screening guidelines.

Doctors consider screening for genetic testing for DICER1 in a person who has at least 1 major feature and 2 minor features as listed below:

Major features:

  • A diagnosis of PPB (any type)

  • A lung cyst in childhood

  • Thoracic embryonal rhabdomyosarcoma, a type of soft-tissue sarcoma

  • Cystic nephroma, a benign kidney tumor

  • Sarcoma in the genitourinary tract, including undifferentiated sarcoma

  • Ovarian Sertoli-Leydig cell tumor

  • Gynandroblastoma, a rare ovarian tumor

  • Uterine, cervical, or ovarian embryonal rhabdomyosarcoma

  • Neuroendocrine tumor in the genitourinary or gynecologic system

  • Thyroid nodules or cancer in 2 or more first-degree relatives (such as a parent or child)

  • Thyroid nodules or differentiated thyroid cancer in childhood

  • Ciliary body medulloepithelioma, a type of childhood eye tumor

  • Nasal chondromesenchymal hamartoma, a benign tumor in the nasal sinus area

  • Pineoblastoma, a cancerous tumor of the brain’s pineal gland

  • Pituitary blastoma, an aggressive tumor of the pituitary gland

Minor features:

  • A lung cyst in an adult

  • Renal (kidney) cysts

  • Wilms tumor, a childhood kidney cancer

  • Thyroid nodules or differentiated thyroid cancer in an adult

  • Embryonal rhabdomyosarcoma not listed under "Major features" (see above)

  • Neuroendocrine tumor that is poorly differentiated

  • Undifferentiated sarcoma somewhere besides the genitourinary tract

  • Macrocephaly, an overly large head size in childhood

  • Childhood cancers associated with any Minor features

    Source: Clinical Cancer Research 2018 May 15;24(10):2251-2261. doi: 10 (Table 1).

If a person is found to have DICER1, doctors will consider screening them further for specific conditions based on specific signs and symptoms that are reported to the doctor or found on a physical exam to look for problems (including those listed above in major and minor features) in these main body systems:

  • Lung system. Symptoms include abnormally rapid breathing, cough, fever, pain, and a collapsed lung. Screening tests include regular chest x-rays or a chest CT scan.

  • Thyroid gland. Symptoms include a nodule or growth on the thyroid gland that is visible or can be easily felt, persistent enlargement of neck lymph nodes, hoarseness, difficulty swallowing, neck pain, and cough. Screening tests include regular thyroid ultrasounds and regular physical exams to check the thyroid.

  • Gynecologic system. Symptoms include dark, coarse, male-pattern hair growth in females, development of other male characteristics such as a deepening voice in females, and abdominal pain, expansion, or a mass. Screening tests include regular pelvic and abdominal ultrasounds.

  • Kidneys/genitourinary system. Symptoms include an abdominal mass or pain, or blood in the urine. Screening tests include regular abdominal ultrasounds.

  • Gastrointestinal system. Symptoms include any sign of intestinal obstruction, such as cramps, constipation, vomiting, or abdominal swelling. Doctors will talk with a person about what screening tests may be appropriate for them.

  • Central nervous system (CNS) and the head and neck system. This includes symptoms that do not involve the thyroid gland (see above), such as headaches, vomiting, double vision, inability to look upward, difficulty walking, premature puberty, Cushing’s syndrome, vision problems, and nasal obstruction. Screening tests include regular physical exams, annual ophthalmologic exam (including visual acuity screening), and magnetic resonance imaging (MRI) for emergency symptoms inside the skull.

    Source: Clinical Cancer Research 2018 May 15;24(10):2251-2261. doi: 10 (Table 2).

The next section in this guide is Symptoms and Signs. It explains what changes or medical problems PPB can cause. Use the menu to choose a different section to read in this guide.