ABSTRACT
Pheochromocytoma is a functioning neoplastic tumor of the adrenal medulla secreting catecholamines derived from sympathogonia of neural crest origin. Similar tumors arise in the sympathetic paraganglia of the thoracolumbar region (extra-adrenal pheochromocytoma); together, they are now known as pheochromocytoma-paraganglioma. This chapter describes the varied clinical presentation caused by high catecholamine secretions. The biochemical assays of catecholamines and metabolites with improvements in imaging techniques that helped earlier diagnosis have been discussed. Cross-sectional CT/MRI and functional MIBG/PET ligand techniques are described. Recent interest has focused on its strong association with familial syndromes, with inheritable mutations detected in as much as 30–40% of cases and at least ten mutations in three clusters of pathophysiology have been documented. The type of mutation has been found to correlate with phenotypic presentation, malignant potential, imaging detectability and outcomes, leading to a recommendation for routine genetic testing. Reports from two centers in India reveal von Hippel-Lindau disease as the commonest familial syndrome. The treatment is primarily surgical with classic open techniques now making way for different minimally invasive approaches. Adequate pharmacological preparation with alpha blockade and expert intraoperative management is the key to an uneventful surgery. The scoring systems of Pheochromocytoma of the Adrenal gland Scaled Score (PASS) and Grading System for Adrenal Pheochromocytoma and Paraganglioma (GAPP) to aid prediction of malignant behavior in the absence of clear histopathological features are described. Tumor recurrence and metastasis is well known and needs a tailored approach. The team needs include members from endocrinology, biochemistry, genetics, surgery, anesthesia and nuclear medicine working together for optimal outcomes.
