PPB is a very rare but important disease. Perhaps 10 - 20 cases per year occur in the United States. However, PPB is critically important to each patient's family and physicians, and it is biologically important because of the family implications in approximately 25% of cases. PPB is too rare to be of interest to most large cancer research groups, but meaningful data on PPB can be collected by a dedicated group like the participants in the International PPB/DICER1 Registry. Please enroll cases in the Registry. The Registry will work with families and physicians on Informed Consent, HIPAA consent, IRB processing, and related issues. Regardless of enrollment status, the Registry will work with families and physicians on any questions related to PPB. Your efforts can make a difference. Thank you.