Target population:

Patients with (1) newly diagnosed or (2) past history of pheochromocytomas and paragangliomas (PPGL) or (3) carrier of genetic mutations in known PPGL susceptibility genes.

International multicenter prospective cohort study with randomized intervention (special care follow-up vs. standard care follow-up).

All patients will receive instructions about follow-up at the time point of study inclusion. Patients randomized to the standard care follow-up group will be advised to return annually for follow-up according to current routine practice (without active re-scheduling). In contrast, patients randomized to the special care follow-up group will also be advised to return annually for follow-up but these patients will be actively invited, re-scheduled and reminded by the centers to meet scheduled follow-up appointments.

The long-term goal of the research planned under this protocol is to reduce morbidity and mortality of patients with PPGLs by improving approaches for management, follow-up and therapy of affected patients. As a first step towards attaining this goal, the primary objective of this protocol is to investigate whether standardized follow-up results in improved long-term outcome in terms of less morbidity and mortality as compared. The central hypothesis is that pro-active, structured and periodic disease screening and management of patients at risk for developing PPGLs and other neoplasms can lead to earlier detection of tumors and reduce adverse outcomes associated with cardiovascular, metabolic and oncologic complications of the tumors than standard care follow-up. The underlying rationale is that establishing improved outcomes for patients at risk for PPGLs will enable evidence-based recommendations for disease follow-up and management, thereby establishing wider acceptance and use of outlined practices with ensuing improvements in the health and quality of life of affected patients and their families.

In addition to the primary objective directed at establishing whether standardized and structured follow-up of patients with an increased risk for new events of PPGL (recurrent tumor, new tumor, or metastases) will result in improved longterm outcome, this protocol will enable several secondary objectives to be addressed using clinical (e.g. age, mode of presentation), biochemical, metabolic and genetic characteristics. These include:

1. to identify prognostic markers of disease progression
2. to assess whether clinical presentation, cardiovascular, metabolic and biochemical phenotype, genetic background and tumor characteristics (location, size, recurrence, pathology) are useful for development of personalized follow-up strategies.
3. to investigate whether standardized follow-up affects quality of life

Inclusion Criteria:

male and female patients (≥ 5 years of age), who fulfill one or more of the following criteria: (i) Patients with a newly diagnosed PPGL. (ii) Patients with a previous history of PPGLs. (iii) Carrier of genetic mutations known to predispose for the development of PPGLs.

All subjects must have read, understood and signed the informed consent form, before inclusion into the study protocol. Signed parental consent must be obtained for children with suspected PPGLs who are enrolled in the study.

Exclusion Criteria:

• Patients with impaired mental capacity that precludes informed consent.
• Pregnancy does not constitute criteria for exclusion from the protocol. However, in pregnant women no Clonidine testing, no PET scanning, MIBG scanning or contrast CT will be performed.
• Patients at risk from injury from the MRI magnet due to implantable metal or who suffer from anxiety in enclosed spaces are excluded from MRI.