Plasma 3, 4-Dihydroxyphenylalanine (Dopa) and Catecholamines in Neuroblastoma or Pheochromocytoma

Abstract

Neuroblastomas and benign and malignant pheochromocytomas are tumors of neural-crest origin that have different clinical characteristics: neuroblastomas are aggressive tumors that occur in children and have no association with hypertension, and pheochromocytomas are slow-growing tumors that occur in both adults and children and have an association with hypertension. Malignant and benign pheochromocytomas cannot be distinguished histologically; malignancies are defined by metastasis. Consistent with their ontogeny, these tumors contain catecholamine precursors, catecholamines, and catecholamine metabolites. Urinary rates of excretion of these substances are key factors in tumor diagnosis. In human urine, the predominant free (unconjugated) catecholamine is dopamine, which probably is