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Pheochromocytoma: A Literature Review

Pheochromocytoma: A Literature Review. Department of Surgery Queen Mary Hospital. Introduction. Tumors arise from enterochromaffin cells in adrenal medulla Release of catecholamines and their metabolites: Epinephrine, norepinephrine, dopamine Metaneprhine, normetaneprhine. Introduction.

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Pheochromocytoma: A Literature Review

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  1. Pheochromocytoma:A Literature Review Department of Surgery Queen Mary Hospital

  2. Introduction • Tumors arise from enterochromaffin cells in adrenal medulla • Release of catecholamines and their metabolites: • Epinephrine, norepinephrine, dopamine • Metaneprhine, normetaneprhine

  3. Introduction • Paragangliomas: • Abdomen – para-aortic region • Thorax • Head & neck

  4. Thoracic Paraganglioma

  5. Presentation • Classical symptoms: • Headache, intense & global in nature (80%) • Palpitation (64%) • Diaphoresis (57%) • Secondary hypertension • Adrenal incidentaloma • Detected by screening in patients with predisposing syndromes

  6. Genetic Abnormalities • Genetic mutations known to associate with pheochromocytoma: • VHL (von Hippel Lindau) • RET (rearranged during tranfection) • SDHB & SDHD (mitochondrial succinate dehydrogenase enzyme complex subunit B & D) • NF1 (neurofibromin 1)

  7. Genetic Abnormalities

  8. Genetic Abnormalities • Cluster 1: VHL, SDHB, SDHD increased intracellular concentration of HIF (hypoxia-induced factor) and angiogenesis • Cluster 2: RET, NF1 increased activation of signaling pathway related to RNA synthesis & metabolism

  9. Biochemical testing

  10. Biochemical testing • 24-hour urine catecholamines & metanephrines • Plasma metanephrines

  11. Biochemical testing JCEM. 2003;88(10):4533-9.

  12. Biochemical testing Precautions: • Measure 24-hour urinary creatinine to ensure adequate urine sample • Adequate rest before blood taking • Withhold the following drugs: • Labetalol • Tricyclic antidepressants • Buspirone • α-blockers, ß-blockers, diuretics, theophylline, levodopa

  13. Biochemical testing • Avoid the following clinical scenarios: • Acute myocardial infarction • Congestive heart failure, NYHA class 3 or 4 • Cerebrovascular accidents • Hypoglycaemia • Alcohol withdrawal • Other stress condition

  14. Biochemical testing • Tests not suggested for diagnosis of pheochromocytoma: • Plasma catecholamines • Urinary vanillylmandelic acid (VMA) • Chromogranin A

  15. Pharmacological testing • Clonidine suppression test • Glucagon stimulation test

  16. Localization imaging • CT • MRI • 131/123I-MIBG (metaiodobenzylguanidine) • PET CT with different tracers

  17. CT CT Eur Radiol. 2007;17:2804-09.

  18. MRI Eur Radiol. 2008;18:2885–92.

  19. 123I-MIBG

  20. PET CT • 18F-FDG(18F-fluoro-2-deoxy-D-glucose) • 18F-FDA (18F-fluorodopamine) • 18F-DOPA (18F-3,4-dihydroxyphenylalanine) • 68Ga-DOTA-NOC (68Ga-[1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid]-1-NaI3-octreotide)

  21. PET CT J Clin Endocrinol Metab. 2009;94(12):4757–4767.

  22. PET CT MEN 2, VHL, SDHD J Clin Endocrinol Metab. 2009;94(12):4757–4767.

  23. PET CT • 68Ga-DOTA-NOC • Pheochromocytoma (and paraganglioma) also express somatostatin receptor (SSTR) • Sensitivity = 100% • Specificity = 85.7% • Accuracy = 98% Eur Radiol. 2012 Mar;22(3):710-9.

  24. Medical therapy • Purpose: • Control blood pressure and heart rate • Prevent intraoperative hypertensive crisis

  25. Medical therapy • Phenoxybenzamine (POB) • Long acting, irreversible, non-selective α-blocker • Reflex tachycardia & postoperative hypotension • Prazosin, terazosin, doxazosin • Selective α1-blocker  no reflex tachycardia • Short acting  lower incidence of post-op hypotension

  26. Medical therapy • Calcium channel blockers • Direct arteriolar smooth muscle relaxation • No postural hypotension • Prevent coronary vasospasm & myocarditis • Use in combination with selective α1-blocker Surgery 106:1149–1154

  27. Is pre-op alpha-blockade necessary? • 30% of patients received no pre-medication • No major cardiovascular complication

  28. Surgical treatment • Open • Laparoscopic: • Absolute contraindications: • Excessive cardiopulmonary risks • Relative contraindications: • Large tumors • Severe obesity • Previous abdominal operations • Malignant tumors

  29. Positioning for Laparoscopic Approach

  30. Head end ASIS Foot end

  31. Head end Xiphoid process Costal margin 1st 12mm port Surgeon’s side 2nd 12mm port (camera) 4th 5mm port 3rd 12mm port ASIS Foot end

  32. Surgical treatment • Intra-operative Hemodynamic Parameters UROLOGY 55(3):340-3

  33. Surgical treatment • Operative Outcome UROLOGY 55(3):340-3

  34. Follow Up National Comprehensive Cancer Network (NCCN) guideline • Every 6 months in 1st to 3rd years • Annually after 4th year • History & physical examination • Blood pressure • Biochemical testing • Regular imaging not suggested

  35. Unresectable Disease • Blood pressure and symptom control • Cytoreductive surgery • Transarterial chemoembolization (TACE) • 131I-MIBG • 90Y/177Lu labeled octreotide • Chemotherapy (CVD or temozolomide) • Sunitinib

  36. Future Prospects • Diagnostic localization technique • Genetic abnormalities • Predicting malignant potential of primary tumour • Treatment of unresectable disease

  37. Conclusion • Studying the genomics of pheochromocytoma aids early detection and development of novel therapy. • Localization of metastatic lesions is improved by PET CT using new tracer nuclides. • Management of pheochromocytoma require multidiciplinary approach.

  38. Thank you

  39. Biochemical testing • Low risk group: • Poorly controlled hypertension • Incidentaloma with adrenocortical phenotype • 24-hr urinary catecholamines & metanephrines • High risk group: • Personal/family history of pheochromocytoma • Predisposing syndrome • Vascular adrenal tumor on imaging  Plasma metanephrines

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