Diagnosis and management of pheochromocytoma: a practical guide to clinicians

Pheochromocytomas (PCCs) are rare catecholamine producing neuroendocrine tumors. The majority of these tumors (85 %) arise from the adrenal medulla. Those arising from the extra-adrenal neural ganglia are called paragangliomas (PGLs). Paroxysmal hypertension with sweating, headaches and palpitation are the usual presenting features of PCCs/ PGLs. Gene mutations are reported in 32-79 % of cases, making genetic screening mandatory in all the cases. The malignancy rates are 10-15 % for PCCs and 20-50 % for PGLs. Measurement of plasma or 24-hour urinary fractionated metanephrines is the best biochemical diagnostic test. Computed tomography or magnetic resonance imaging has high sensitivity (90-100 %) and reasonable specificity (70-90 %) for the anatomical localization. The functionality is assessed by different radionuclide imaging modalities such as metaiodobenzylguanidine (MIBG) scintigraphy, positron emission tomography or single photon emission computed tomography. The only modality of curative treatment is tumor excision. Proper peri-operative management improves the surgical outcomes. Annual follow up with clinical and biochemical assessment is recommended in all the cases after treatment. Children, pregnant women and older people have higher morbidity and mortality risk. De-bulking surgery, chemotherapy, radiotherapy, molecular agents like sunitinib and everolimus, radionuclide agents and different ablation procedures may be useful in the palliation of inoperable/metastatic disease. An update on the diagnostic evaluation and management of PCCs and PGLs is presented here.