The role of chromogranin A in the management of patients with phaeochromocytoma.
Chromogranin A (CgA) is the most accurate general marker of neuroendocrine tumours. Supranormal CgA concentrations have been recorded in patients with tumours of neuroectodermal origin such as phaeochromocytoma and paraganglioma. The present study was performed to assess the role of CgA determination in the management of patients with phaeochromocytoma, in comparison with urinary catecholamines and their metabolites. The patients studied included 22 cases with phaeochromocytoma at initial presentation or at relapse some years after surgical cure or during follow-up of a malignant phaeochromocytoma. Seventeen patients were evaluated before and after surgical removal of phaeochromocytoma. To assess the specificity of the hormonal parameters, 20 subjects were enrolled as controls; they were from a group of patients referred to our observation for possible phaeochromocytoma and who were subsequently proven not to have the disease. Urinary epinephrine and norepinephrine were supranormal in 82% and 77% of patients, respectively. Urinary metanephrines and normetanephrines were supranormal in 84% and 89% of patients, respectively. The combination of urinary metanephrine and normetanephrine had a sensitivity of 100% in identifying a phaeochromocytoma. CgA was supranormal in 91% of patients. Combining the results of CgA and urinary catecholamines (epinephrine and norepinephrine), the sensitivity for diagnosis of phaeochromocytoma was 100%. Urinary catecholamines, metabolites (metanephrine and normetanephrine) and CgA levels in patients with malignant phaeochromocytoma did not differ significantly from those of patients with benign lesions. In most cases, CgA normalized after surgery. Our results indicate that CgA is a good marker of phaeochromocytoma; measurement of CgA could have a role in the follow-up of patients operated on for phaeochromocytoma.