Lecture on Diagnostics of Pheochromocytoma and Paraganglioma

Introduction

• Speaker: Member of the Medical Advisory Board for a Fiopera Alliance.
• Topics: Diagnostics of pheochromocytoma and paraganglioma.
• Focus: Screening tests and diagnostic imaging.

Case Study

• Patient: 39-year-old woman with past adrenal pheochromocytoma.
• Symptoms: Sweating, palpitations, headaches.
• Concerns: Possible recurrent or new pheochromocytoma.

Screening Tests

• Plasma Tests: Plasma-free metanephrines.
• Urine Tests: 24-hour urine fractionated metanephrines and catecholamines.
• Equivalence: Plasma and urine tests are quite equivalent.
• Practical Approach: Plasma tests preferred for ease.
• Factors: Different ranges for hypertensive patients and posture.
• Guidelines: Endocrine Society suggests lying down for 30 minutes before blood draw.

Indeterminate Levels

• True levels: 2-4 times upper limit for plasma; 3-5 times for urine.
• Borderline Values: Require further testing or change in patient posture.
• Renal Disease: Urine tests less reliable.
• Plasma Catecholamines: Useful for dopamine secretion in SDH pathogenic variants.

Chromogranin A

• Co-stored/co-secreted with catecholamines.
• High sensitivity but low specificity.
• Elevation: Common with pheo and para, but also affected by proton pump inhibitors.

Managing Indeterminate Biochemistries

• Medication Interference: Check medication and supplement list.
• Common Interferences: SSRIs, muscle relaxants, marijuana.
• Imaging Consideration: If high pre-test probability or high test results.

Imaging for Tumor Localization

• CT and MRI: First choice for primary tumor localization.
• Functional Imaging: Reserved for specific cases due to cost and radiation.
• Pheochromocytomas: Classic appearance on CT/MRI; Hansfeld units >10.
• Functional Imaging: Consider for extra-adrenal paragangliomas or non-secreting tumors.

Functional Imaging Techniques

• MIBG Imaging: Uses net transporter; 60% avidity.
• Limitations: Normal adrenal glands can show uptake.
• DOTATATE PET: Uses somatostatin receptor; useful for metastatic disease.

Biopsy Considerations

• Risk: High risk of catecholamine surge, not recommended without alpha blockade.

Genetic Testing and Screening

• Importance of genetic testing for ongoing screening and risk assessment.
• Predictors: SDHB variants, extra-adrenal tumors, large size.
• Pathology: Current scoring systems not predictive for metastatic disease.

Questions and Discussion

• Patient Advocacy: Importance of patient knowledge and advocacy in healthcare.
• Educational Efforts: Conferences and clear communication between patients and healthcare providers.
• Handling Adenomas: Proper radiological evaluation and biochemical testing needed.

Conclusion

• Thank You: Appreciation for patients and families participating in research.
• Future Directions: Need for continued education and research in diagnostics.