To investigate changes in preoperative clinical features and the long-term outcome of tumor recurrence, mortality, and morbidity in patients with pheochromocytoma, we retrospectively examined changes in the clinical features by comparing 49 patients from 1957 to 1985 (group I) with 46 patients from 1986 to December 1995 (group II). In addition in these 95 patients (excluding 2 who had died before operation), we evaluated long-term postoperative outcome from the initial operation to August 1996 (909 patient-years). The mean age in group II was older than that of group I. The percentage of patients having proteinuria or hypertensive retinopathy in group II was less than that in group I. Of 20 patients with incidentally discovered pheochromocytoma, 7 (35%) were > or =60 years old, 7 asymptomatic, and 11 (55%) normotensive. Plasma and urinary catecholamines in these patients were significantly (P < .01) lower than in patients with pheochromocytoma having typical clinical features. Long-term cohort study showed 14 deaths. Relative survival rates were 91% at 5 years and 83% at 10 years and unchanged thereafter. The Kaplan-Meier estimate of pheochromocytoma-free survival was shorter in patients with a larger-than-median (60 g) tumor weight. Six patients had malignant recurrence 3 to 101 months (median, 45 months) after the initial operation. Of 65 patients confirmed alive at follow-up, 11 were hypertensive. In the Cox model, hypertension-free survival was not associated with age, a family history of hypertension, duration of hypertension, or creatinine clearance. Pheochromocytoma should be diagnosed from a wide spectrum of clinical features including those that are not generally suspected of resulting from excess catecholamines or hypertension, and after surgery, patients with this disease should be followed-up carefully for a long period (at least 10 years) because of the risk of tumor recurrence and the high prevalence of disease.

Plasma levels of chromogranin A (CgA) were measured by ELISA in 22 patients with pheochromocytoma (18 non-metastatic, 3 metastatic, and 1 mixed neuroendocrine-neural tumor), 9 patients with primary hyperparathyroidism, and 9 patients with pituitary adenoma. The plasma levels of CgA were compared with norepinephrine, epinephrine, parathyroid hormone and pituitary hormones, i.e., growth hormone and prolactin. In pheochromocytoma, CgA in preoperative plasma of the patients without metastasis was 228 +/- 38 U/L (mean +/- SEM) and significantly higher than healthy controls (30 +/- 11 U/L, n = 40). Plasma CgA was decreased after removal of the tumors (28 +/- 6.0 U/L), except in three patients with metastatic pheochromocytoma and a mixed neuroendocrine neural tumor. The concentration of CgA in the patients with non-metastatic pheochromocytoma was significantly correlated with that of plasma norepinephrine (P < 0.005, r = 0.68) and urinary norepinephrine (P < 0.05, r = 0.65), but not with that of epinephrine. There was an exceptional case in which CgA was extremely high, but the CA level was normal. This tumor was a highly malignant pheochromocytoma with extensive metastases composed of small tumor cells which were occasionally positive for tyrosine hydroxylase immunohistochemically. These cells were considered to be poorly differentiated tumor cells and synthesized a very small amount of norepinephrine. Plasma levels of the patients with primary hyperparathyroidism and the patients with pituitary adenoma were 44 +/- 4 U/L and 48 +/- 8 U/L, respectively. Only one patient with a growth hormone-producing pituitary adenoma had a high level of CgA. Plasma CgA is a useful tumor marker for pheochromocytoma, even for malignant pheochromocytoma without elevated CA level, but not for hyperparathyroidism, or pituitary adenoma.

Despite the widespread distribution of chromogranin A (CgA) in neuroendocrine tissues, the biological function of CgA has not yet been elucidated. The primary amino acid sequence of CgA, elucidated by cDNA analysis, has been revealed to include several pairs of basic amino acid residues that are homologous to the bioactive peptides, such as pancreastatin (PST) and chromostatin (CST). Using antibodies for human PST and CST, the immunohistochemical localization of these peptides was investigated in neuroendocrine tissues, including human pituitary glands, pancreas, adrenal medulla, various types of neuroendocrine neoplasms (13 pheochromocytomas, 10 medullary thyroid carcinomas, 11 pancreatic endocrine tumors, and 19 carcinoid tumors), and the cell line QGP-1N derived from human somatostatin-producing pancreatic endocrine tumor. Variable immunoreactive intensities of PST and CST were seen, but both peptides were detectable in all neuroendocrine tissues and in most of the neoplasms. Immunoreactivity for both PST and CST was observed in 100 and 73%, respectively, of pancreatic endocrine tumors, all pheochromocytomas, and 80 and 40%, respectively, of medullary thyroid carcinomas, as well as all nonrectal carcinoid tumors. In rectal carcinoids, cells immunoreactive for PST and CST were sparse. The distribution of PST and CST was similar to that of CgA, and it is considered that these peptides are simultaneously processed from CgA, and may play roles in autocrine and paracrine regulation on various hormones in addition to their previously known functions.

No abstract

Dopamine (DA) is the most abundant catecholamines in human plasma and exists mostly in the sulfoconjugated form (DA sulfate), a biologically inactive metabolite. The paucity of unconjugated DA (PDA) in plasma throws doubt on its physiological significance. However, PDA, when measured with a highly sensitive radioenzymatic method, showed quite different features from norepinephrine and epinephrine in some types of clinical hypertension, lower in essential hypertension and higher in primary aldosteronism and pheochromocytoma. There was a weak but significant correlation between the values of PDA and DA sulfate measured in the same specimens, but DA sulfate was more susceptible to impaired renal function. Upright posture, high salt diets and an intravenous injection of metoclopramide (MCP, 10 mg), a DA receptor antagonist, induced a slight but significant increase in PDA in normal and hypertensive subjects. An intravenous dexamethasone (2 mg) caused a gradual increase in PDA over 150 min after medication, which was completely blocked by concomitant administration of a-methyl p-tyrosine, a tyrosine hydroxylase inhibitor. The responses of PDA to both high salt diets and MCP were blunted in salt-sensitive patients with uncomplicated essential hypertension. The results suggest that DA is not only a precursor of norepinephrine biosynthesis but also plays an inherent role as an active neurotransmitter in the peripheral sympathoadrenal system, and that PDA is a sensitive marker of peripheral dopaminergic activity, which may operate to modulate the cardiovascular and endocrine functions and participate in the pathogenesis of some types of hypertension. (Hypertens Res 1995; 18 Suppl. I: S65-S72)