Measurement of urinary epinephrine in screening for pheochromocytoma in multiple endocrine neoplasia type II

Questioning the pathogenic role of the pTyr791Phe mutation of the RET proto-oncogene: Insight from a case report

The pTyr791Phe mutation of the RET proto-oncogene is associated with a low penetrance of medullar thyroid carcinoma (MTC). Thus, there is a lack in guidelines on management of these patients presenting without a thyroid disease.

CLINICAL CASE

A 27-year-old woman presented with a history of severe hypertension, paroxysmal tachycardia, diaphoresis and headaches. Twenty-four-hour urinary norepinephrine and normetanephrine levels were exclusively up to 20 times the normal limit. CT-scan and MRI found a 35-mm diameter right adrenal tumor, highly intense in T2- and hypo-intense in T1-weighted image, enhanced after gadolinium injection. After alpha-adrenergic blocker treatment, a surgical resection of the tumor was performed; this latter proved to be a pheochromocytoma. Genetic screening only revealed a germline pTyr791Phe mutation of the RET proto-oncogene. However, the patient showed no evidence of MEN2: basal calcitonin was normal and calcium infusion test was negative. Thyroid ultrasound revealed a TIRADS 3 nodule with benign cytology. Total thyroidectomy was suggested but withheld due to the patient's refusal and a close follow-up was decided.

CONCLUSION

This rare case of pTyr791Phe mutation-related pheochromocytoma without evidence of MTC questions the indication for prophylactic thyroidectomy in mutation carriers, as recent data challenges its pathogenicity.

Positive correlation between urinary excretion of catecholamine metabolites and tumour mass in pheochromocytoma. Results in patients with sustained and paroxysmal hypertension and multiple endocrine neoplasia

In a series of 53 pheochromocytoma patients operated on at Sahlgren's Hospital during 1956-82, a positive linear correlation is established between the 24-hour urinary excretion of vanilmandelic acid (mumol/24 h) and tumour mass (g). A similar correlation was found between the excretion of metanephrines and tumour mass in 33 subjects. The patients were subgrouped according to their type of hypertension. A statistically significant correlation between vanilmandelic acid excretion and tumour mass persisted in groups IA (sustained hypertension without attacks), IB (sustained hypertension with attacks), and II (paroxysmal hypertension) but not in group III (miscellaneous patients). There was also a correlation between metanephrine excretion and tumour mass in groups IB (n = 8) and II (n = 12). In 10 patients with the syndrome of multiple endocrine neoplasia, a positive correlation was found between tumour mass and the excretion of vanilmandelic acid, metanephrines and adrenaline.

Review: Should patients with apparently sporadic pheochromocytomas or paragangliomas be screened for hereditary syndromes?

CONTEXT

The recent identification of germline mutations of the mitochondrial complex II genes in variants of paraganglioma/pheochromocytoma syndrome has enlarged the number of known causative genes for hereditary pheochromocytoma. A question confronting clinicians is whether they should screen patients with apparently sporadic pheochromocytomas for unsuspected germline mutations of some or all of the seven genes known to cause hereditary paraganglioma or pheochromocytoma (NF1, VHL, RET, MEN1, SDHD, SDHC, and SDHB). A positive answer was suggested by a report that placed the estimate of hereditary disease in apparently sporadic pheochromocytoma as high as 24%.

EVIDENCE ACQUISITION

We applied clinically useful criteria to a review of the literature, defining cases of apparently sporadic pheochromocytoma as those without a suspicious personal or family history, with a focal, unilateral pheochromocytoma, and presenting at age less than 50 yr.

EVIDENCE SYNTHESIS

We reduced the overall estimate of unsuspected hereditary pheochromocytoma patients with apparently sporadic pheochromocytoma to approximately 17%. Mutations in only three genes (VHL, SDHB, and SDHD) accounted for almost this entire minority, and unsuspected RET mutation was rare. Costs, coverage by insurance, the potential effect on insurability, and deficient information for populations outside of referral centers should be considered before recommending genetic testing in patients with apparently sporadic presentations of pheochromocytomas.

CONCLUSION

We recommend genetic testing for patients with an apparently sporadic pheochromocytoma under the age of 20 yr with family history or features suggestive of hereditary pheochromocytoma or for patients with sympathetic paragangliomas. For individuals who do not meet these criteria, genetic testing is optional.

Plasma normetanephrine and metanephrine for detecting pheochromocytoma in von Hippel-Lindau disease and multiple endocrine neoplasia type 2

BACKGROUND

The detection of pheochromocytomas in patients at risk for these tumors, such as patients with von Hippel-Lindau disease or multiple endocrine neoplasia type 2 (MEN-2), is hindered by the inadequate sensitivity of commonly available biochemical tests. In this study we evaluated measurements of plasma normetanephrine and metanephrine for detecting pheochromocytomas in patients with von Hippel-Lindau disease or MEN-2.

METHODS

We studied 26 patients with von Hippel-Lindau disease and 9 patients with MEN-2 who had histologically verified pheochromocytomas and 50 patients with von Hippel-Lindau disease or MEN-2 who had no radiologic evidence of pheochromocytoma. Von Hippel-Lindau disease and MEN-2 were diagnosed on the basis of germ-line mutations of the appropriate genes. The plasma concentrations of normetanephrine and metanephrine were compared with the plasma concentrations of catecholamines (norepinephrine and epinephrine) and urinary excretion of catecholamines, metanephrines, and vanillylmandelic acid.

RESULTS

The sensitivity of measurements of plasma normetanephrine and metanephrine for the detection of tumors was 97 percent, whereas the other biochemical tests had a sensitivity of only 47 to 74 percent. All patients with MEN-2 had high plasma concentrations of metanephrine, whereas the patients with von Hippel-Lindau disease had almost exclusively high plasma concentrations of only normetanephrine. One patient with von Hippel-Lindau disease had a normal plasma normetanephrine concentration; this patient had a very small adrenal tumor (<1 cm). The high sensitivity of measurements of plasma normetanephrine and metanephrine was accompanied by a high level of specificity (96 percent).

CONCLUSIONS

Measurements of plasma normetanephrine and metanephrine are useful in screening for pheochromocytomas in patients with a familial predisposition to these tumors.

Differential diagnosis of hot flashes

OBJECTIVE

The purpose of this study is to present the physiology and differential diagnosis of hot flashes, other than associated with menopause, in order to facilitate the proper evaluation of symptomatic patients with hot flashes.

STUDY DESIGN

Literature search using Med-Line computer access.

RESULTS

Interest in flushing reaction began in historic times. With the rapidly expanding population of women over the age of 45 and prevalence of hot flashes as menopausal symptoms, physicians need to be aware of other medical conditions which may mimic hot flashes. These include flushing due to systemic diseases, carcinoid syndrome, systemic mast cell disease, pheochromocytoma, medullary carcinoma of the thyroid, pancreatic islet-cell tumors, renal cell carcinoma, neurological flushing, emotional flushing, spinal cord injury, flushing reaction related to alcohol and drugs, flushing associated with food additives and eating.

CONCLUSION

There is a wide variety of disease processes that can cause hot flashes. Knowledge of the nature of these disease processes is necessary for quick recognition of patients with hot flashes who do not respond to estrogen replacement treatment, and to facilitate the proper evaluation of atypical patients.

Phaeochromocytoma in multiple endocrine neoplasia type 2 A: survey of 100 cases

OBJECTIVE

We report clinical, biochemical, morphological and histological data of phaeochromocytoma in 40 French families and in apparently sporadic cases of multiple endocrine neoplasia (MEN) type 2 A (medullary thyroid carcinoma, phaeochromocytoma, with or without hyperparathyroidism).

DESIGN

This retrospective study was obtained from cases registered by the 'Groupe d'Etudes des Tumeurs à Calcitonine' from 1968 to 1990. We analysed the cases having sufficiently precise data on phaeochromocytoma with Pigas Software.

PATIENTS

Characteristics of phaeochromocytoma in 100 patients with MEN 2 A were reviewed. Phaeochromocytoma was bilateral in 51%. The disease was inherited in 94 patients from 40 families (40 probands, 54 relatives), and was apparently sporadic in six.

RESULTS

In this series, diagnostic circumstances were highly suggestive of phaeochromocytoma in 39.8% of the cases, whereas in 43.2%, diagnosis was made through systematic investigations of patients, either before (27.3%) or after (13.6%) thyroidectomy, or after discovery of hyperparathyroidism (2.3%). Fifteen per cent of patients were detected by family screening. Sudden death occurred in 8.9%, malignant phaeochromocytoma in 3%, and ectopic tissue in 4% of the cases. Urinary metanephrines appeared to be the most sensitive screening test. The extent of clinical symptoms was not associated with a particular hormonal pattern. Bilateral adrenalectomy was performed in 60% (in one step in 50%, in two steps in 10%). In these patients, bilateral histological lesions were observed in 92.5%. Simultaneous diagnosis for adrenal and thyroid disease was made in 73.4%, but phaeochromocytoma may be diagnosed before (9.6%) or after (17%) medullary thyroid carcinoma, with an interval greater than 2 years in 25 cases.

CONCLUSION

Owing to variable clinical symptoms of phaeochromocytoma in these 100 cases of MEN 2 A, systemic biological adrenal assay is required. The search for phaeochromocytoma in medullary thyroid carcinoma (and vice versa) has to be systematically performed, even in apparently sporadic cases. Screening for phaeochromocytoma must be repeated for years, owing to the frequency of bilateral adrenal disease.

The impact of recent advances in diagnostic technology on the clinical presentation of phaeochromocytoma

OBJECTIVE

To examine the impact of recent advances in diagnostic technology on the spectrum of clinical and biochemical features of patients presenting with a new diagnosis of phaeochromocytoma.

DESIGN

A retrospective review of the clinical and biochemical features of patients diagnosed by our laboratory as having phaeochromocytoma within a 27-month period up to December, 1990. Noradrenaline, adrenaline and dihydroxyphenylglycol were assayed in 24-hour urine specimens (19 patients) or plasma (1 anuric patient) by gas chromatography/mass spectrometry.

SETTING

A tertiary level chemical pathology department.

PATIENTS

Twenty patients with a new diagnosis of phaeochromocytoma.

RESULTS

The classic, episodic adrenergic symptoms traditionally associated with phaeochromocytoma were absent in 9 of the 20 patients (45%). "Atypical" phaeochromocytoma presented as a mass on computed tomography imaging (6 patients, 30%), "phaeochromocytoma crisis" (4 patients, 20%) or family screening (1 patient, 5%). Excessive adrenaline production was found in 11 patients (55%) and six (30%) had predominantly adrenaline-secreting tumours. The urinary noradrenaline:dihydroxyphenylglycol ratio was raised in all nine patients with predominantly noradrenaline-secreting tumours but was not raised in nine out of ten patients with adrenaline-secreting phaeochromocytoma. Adrenaline excretion was significantly correlated with tumour size (r = 0.8; P less than 0.05).

CONCLUSIONS

Advances in diagnostic technology, particularly specific adrenaline assays and computed tomography, have made possible the early diagnosis of patients with phaeochromocytoma presenting in ways previously thought to be uncommon. All patients with adrenal masses noted incidentally on CT scan should be investigated for phaeochromocytoma. Adrenaline-secreting tumours are common and both noradrenaline and adrenaline should be assayed in all patients investigated for phaeochromocytoma.

High permanent plasma adrenaline levels: a marker of adrenal medullary disease in medullary thyroid carcinoma

Increases in urinary, plasma and tumour adrenaline have been previously observed in MEN II patients with phaeochromocytoma. However, the sensitivity of adrenaline for early detection of adrenal medullary disease has not been accurately evaluated. Twenty-five patients with medullary thyroid carcinoma (MTC) histologically confirmed but without clinical or biological evidence of phaeochromocytoma have been studied. Medullary adrenal status was evaluated by adrenal CT-scan. MIBG scintigraphy, determination of urinary VMA, metanephrines and total catecholamine levels, measurement of nyctohemeral plasma adrenaline or noradrenaline concentrations (every 2 h during 24 h) and clonidine suppression test. Four of the 25 patients had evidence of adrenal medullary disease in view of the coexistence of CT-scan, MIBG scintigraphy and plasma adrenaline abnormalities. Moderate adrenal enlargement (unilateral, n = 3; bilateral, n = 1) was observed on scans together with a high adrenal MIBG uptake (bilateral, n = 4). Among the urinary parameters studied, a minor MN increase was observed in only one of the four patients. Plasma adrenaline levels were significantly (P less than 0.01) different from those of the other 21 patients (mean + SD 115 + 110 pmol/l). This plasma adrenaline increase is reproducible and not suppressed by clonidine. Unilateral adrenalectomy performed in one patient confirmed a phaeochromocytoma and induced normalization of plasma adrenaline levels. In contrast, the plasma noradrenaline levels of the four patients were not statistically different from those of the other 21 patients. These data suggest that persistent high plasma adrenaline levels may be selectively increased in MTC patients together with a moderate adrenal CT-scan enlargement and a high adrenal MIBG uptake, despite a normal urinary excretion of total catecholamines and catecholamines metabolites.(ABSTRACT TRUNCATED AT 250 WORDS)

Phaeochromocytomas secreting adrenaline but not noradrenaline do not cause hypertension and require precise adrenaline measurement for diagnosis

1. Urinary noradrenaline (NA) and adrenaline (ADR) determinations are a more sensitive index than plasma measurements for the diagnosis of phaeochromocytoma (phaeo). 2. Even though urinary NA excretion serve as a sufficient single diagnostic test for the majority of phaeos, it is necessary to measure urinary ADR excretion if ADR-only secreting phaeos are not to be missed, particularly in patients with multiple endocrine neoplasia (MEN) syndrome. 3. The clonidine suppression test confirmed all tumour diagnoses, and in this series was not responsible for any false negative or false positive results.

Overnight clonidine suppression test in the diagnosis and exclusion of pheochromocytoma

In a prospective study designed to differentiate pheochromocytoma from other forms of hypertension, urinary catecholamines were measured after sleep and clonidine administration in 12 patients with pheochromocytoma, 19 hypertensive patients in whom pheochromocytoma was suspected but later excluded, and 31 hypertensive patients in whom pheochromocytoma was never suspected. The test correctly identified all 12 patients in whom pheochromocytoma was present. Four of these had equivocal plasma levels of both norepinephrine and epinephrine, suggesting that overnight clonidine suppression may be of particular value when tumor secretion is intermittent or low. When pheochromocytoma was not present, urinary norepinephrine and epinephrine levels were suppressed below 60 and 20 nmol/mmol creatinine, respectively, after sleep and clonidine, the two in combination giving better suppression than sleep alone. Since urinary catecholamines can be determined relatively easily by high-pressure liquid chromatography with electrochemical detection, this test may be more widely applicable than suppression tests based on plasma measurements.

The clinical outcome of prospective screening for multiple endocrine neoplasia type 2a. An 18-year experience

An important question facing physicians who care for families with multiple endocrine neoplasia type 2a is whether prospective screening to detect early abnormalities of the thyroid, parathyroid, or adrenal glands favorably influences the ultimate course of the disease. An 18-year study of a large family has allowed us to examine the effect of early treatment on the clinical course of the disease. Of 22 patients who underwent thyroidectomy for early C-cell abnormalities, 19 remained free of detectable medullary thyroid carcinoma according to all criteria, at a mean of 11 years after thyroidectomy. None of the 22 patients had evidence of parathyroid disease either at the time of surgery or after a mean follow-up of 10 years. Prospective screening for adrenal medullary abnormalities by means of measurement of 24-hour urinary epinephrine excretion and the ratio of urinary epinephrine to norepinephrine was predictive of pheochromocytoma in 10 of 11 patients (with a false negative result in one patient) but was not useful in diagnosing adrenal medullary hyperplasia. We conclude that regular, prospective screening and early treatment of the manifestations of multiple endocrine neoplasia can prevent metastasis of medullary thyroid carcinoma and the morbidity and mortality caused by pheochromocytoma.

Phaeochromocytoma

Phaeochromocytomas are uncommon among patients with hypertension, and sometimes occur in persons without known hypertension, but are important to detect because they are often lethal but commonly curable, and because they are a clue to the presence of associated conditions. Paroxysmal symptoms (especially headache, palpitations, diaphoresis and anxiety), hypertension that is intermittent, unusually labile or resistant to conventional therapy, and conditions known to be associated raise the clinical suspicion of phaeochromocytoma. Biochemical confirmation is commonly achieved by measurement of urinary catecholamines, metanephrines or VMA. Plasma noradrenaline and adrenaline measurements may be superior to measurements of urinary catecholamine metabolites, but strict attention to the details of sample collection, handling and storage, the many sources of possible biological variation and the effects of drugs is critical if diagnostic error is to be avoided. Patients should be evaluated in the drug-free state if at all possible. Anatomical localization, in the abdomen in the vast majority of cases and usually in the adrenal medullae, can generally be accomplished with computed tomographic scans. Bilateral adrenomedullary tumours are the rule in familial phaeochromocytoma. Most phaeochromocytomas are benign and can be excised totally after medical preparation with an alpha-adrenergic antagonist.

Plasma norepinephrine and epinephrine responses to glucagon in patients with suspected pheochromocytomas

Plasma norepinephrine and epinephrine levels were measured before and after glucagon administration in 28 patients suspected of having a pheochromocytoma: three patients were subsequently found to have tumors. The norepinephrine response predicted the presence or absence of a tumor in 27 of the 28 patients. Epinephrine levels doubled, on the average, in patients who did not have pheochromocytomas, and were not useful in distinguishing the patients with or without tumors. A comparison of the response to glucagon and a placebo indicated that changes in plasma catecholamine levels were hormone-related and not the result of side-effects accompanying injection. The glucagon provocation test, with measurement of plasma norepinephrine and epinephrine levels, may be a useful adjunctive tool for evaluating patients suspected of having a pheochromocytoma when performed according to a standardized protocol and interpreted in relation to appropriate controls.

Hypertension: strategies for laboratory diagnosis

Although surgically correctable causes account for relatively few cases of hypertension, laboratory investigation is warranted if clinical clues are present. Pheochromocytoma, which triggers hypertension by producing excess catecholamines, can be identified by detecting metabolites of these substances in urine. An abnormal intravenous pyelogram suggests renovascular hypertension, but for definitive diagnosis, bilateral renal vein renin measurements are necessary. In primary aldosteronism, with its characteristic hypokalemia, serum potassium determination remains the most feasible, if not the most accurate, detection method.

Random one-hour urine catecholamine and 4-hydroxy-3-methoxymandelic acid assays for diagnosis of pheochromocytoma

Using randomly voided 1-h urine samples, levels of excretion of catecholamines (CA) and 4-hydroxy-3-methoxymandelic acid (vanillylmandelic acid; VMA) were determined in order to save time in and simplify the diagnostic work-up of pheochromocytoma, particularly in out-patient hypertension clinics. Twenty-nine patients with surgically verified pheochromocytoma (15 paroxysmal and 14 sustained type), 56 patients with essential hypertension (26 labile and 30 fixed type) and 14 normal volunteers were studied. Abnormally high excretion of CA and VMA was found in all patients with pheochromocytoma when compared to those with essential hypertension or to normal controls after duly considering the influence of external factors such as food and exercise. From these results, we concluded that assays of CA and VMA even in random 1-h urine samples are useful in separating patients with pheochromocytoma from those with other types of hypertension.