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PubMed2006

Analysis of large versus small pheochromocytomas: operative approaches and patient outcomes.

BACKGROUND: Laparoscopic adrenalectomy for small pheochromocytomas, although challenging, is widely accepted. However, its application to pheochromocytomas larger than 6 cm is questioned due to concerns of malignancy and case complexity. Our aim was to examine the impact of pheochromocytoma tumor size (>/=6 cm vs <6 cm) on operative approach and postoperative patient outcomes. METHODS: A retrospective review of adrenalectomies performed at 3 university hospitals over 1 decade was analyzed. All pheochromocytomas were identified and then divided based on size into large (>/=6 cm) and small (<6 cm) groups. We examined patient and tumor demographics, pathologic diagnosis, operative approach (laparoscopic vs open), postoperative complications, and biochemical cure rates. Data were analyzed using the Student t test and Fisher exact test with a P value <.05 considered significant. RESULTS: From 1995 to 2005, 65 pheochromocytomas were resected. Of the total, 38% (n = 25) tumors were >/=6 cm and 62% (n = 40) were <6 cm. For the large tumors, 1 out of 25 (4%) was malignant, whereas no small tumors were malignant. There was no statistically significant increased risk of malignancy in tumors >/=6 cm in size (P = .31). Initial operative approach was based on surgeon preference. Of the adrenalectomies performed, 88% were laparoscopic, with 3 of 25 (12%) large tumors requiring conversion from laparoscopic to open for intraoperative bleeding. None of the small tumors required conversion. No major postoperative complications (eg, stroke or myocardial infarction) occurred in either group. Minor complications (eg, wound infections and hematomas) were noted in 16% of large tumors and 12.5% of small tumors (P = .45). A total of 96% (24 of 25) patients with large tumors and 100% with small tumors showed postoperative biochemical cure. Tumor recurrence was noted in 1 patient with a tumor <6 cm. CONCLUSIONS: Pheochromocytomas >/=6 cm pose a challenge for laparoscopic resection, and concerns have been raised about the validity of this operative approach. This study demonstrates that there is no significant difference in the rate of malignancy for pheochromocytomas >/=6 cm versus <6 cm. There also were no significant differences identified in complication rates, postoperative biochemical cures, or tumor recurrence rates between these groups. Laparoscopic resection of pheochromocytomas can be safely accomplished regardless of size in centers with surgeons experienced in these procedures.

Adrenal Gland Neoplasms↗
PubMed2000

[Pheochromocytoma associated with multiple endocrine neoplasia 2A and sporadic: differential characteristics].

BACKGROUND: To study distinctive clinical features of pheochromocytoma in the setting of multiple endocrine neoplasia type 2A (MEN 2A) in comparison with sporadic pheochromocytoma. PATIENTS AND METHOD: All patients diagnosed of sporadic pheochromocytoma (n = 29) and in the setting of MEN 2A (n = 16) between 1976 and 1998 in a tertiary hospital were included in the study. The following variables were compared: age at diagnosis, symptoms, presence and characteristics of hypertension, size of the tumor, localization and malignancy. The accuracy of diagnostic tests was also evaluated. RESULTS: The pheochromocytoma associated to MEN 2A had a higher prevalence in our study (35.5%) and the diagnosis was performed earlier than for sporadic pheochromocytoma (29.1 [7.8] vs. 47,5 [10. 9] years; p < 0.001). Other distinctive features in comparison with sporadic pheochromocytoma were: bilaterality (81.25 vs. 3.44%; p < 0. 001), absence of symptoms (44 vs 11%; p < 0.05) and paroxysmal hypertension. Concerning the diagnostic tests, it must be noted the low sensitivity (60%) of vanillylmandelic acid in MEN 2A. CONCLUSIONS: The pheochromocytoma in the setting of MEN 2A is diagnosed at younger age and frequently asymptomatic and bilateral. In view of the high prevalence of MEN 2A in our country, a genetic analysis should be performed in all patients with pheochromocytoma, especially when it is bilateral.

Adrenal Gland Neoplasms↗
PubMed1979

Pheochromocytoma--recognition and management.

Pheochromocytoma is an infrequent cause of hypertension. In spite of its rarity, pheochromocytoma has assumed notorious importance because or a wide variety of clinical features associated with this syndrome. Hypertension remains the most important clinical lead. The presence of other features, such as severe headache, perspiration, palpitations or orthostatic hypotension, makes the diagnosis of pheochromocytoma likely. The diagnosis of this condition can be made with greater certainty than that of any other form of secondary hypertension. Pharmacologic tests are no longer used for evaluation purposes. Biochemical tests are the most important aids to diagnosis, provided highly specific methods are used to determine the levels of urinary catecholamines or their metabolites. Interference by various drugs should be avoided. Most of the pheochromocytomas are found in the abdomen, predominantly in the adrenals. Successful outcome of surgery depends critically on adequate preoperative preparation of the patient with adrenergic blocking drugs and proper intraoperative care. Surgery should only be performed in an institution with experience in treating these tumors. Invasive localizing procedures could be dangerous in patients with pheochromocytoma and are best avoided. Medical therapy proves to be quite successful for those patients who are unable or unwilling to undergo surgery and for those with demonstrated malignant tumor. The postoperative course in most instances is uneventful. The physician should be aware of familial forms of pheochromocytomas and screen all the hypertensive members of the patient's family for the presence of this condition. Pheochromocytoma, with its multiple facets, presents a challenge to the clinician; however, with prompt diagnosis and proper treatment, pheochromocytoma can often be cured. The improved management of patients with this potentially lethal condition is the result of better knowledge of biochemical pharmacology, improved preoperative, surgical and postoperative care.

Adrenal Gland Neoplasms↗
PubMed1999

The usefulness of [131I]-metaiodobenzylguanidine ([131I]-MIBG) scintigraphy performed one week after administration in diagnosing pheochromocytoma.

BACKGROUND: Imaging performed 36-48 h after metaiodobenzylguanidine (MIBG) injection is being widely used in the diagnosis of pheochromocytoma. However, there are some difficult cases to diagnose due to a high concentration of MIBG remaining in the background. We studied the significance of scans on the 7th day after MIBG injection when the concentration of MIBG in the background has declined. METHODS: Imaging was carried out on 11 cases before operation, five cases (eight times) after operation and 12 cases which had been strongly suspected of being pheochromocytoma, but later proved to be non-pheochromocytoma. RESULTS: In all the cases of pheochromocytoma, except one, the tumor imaging was clear 24-72 h after MIBG injection. As for the images after operation and those of the 12 non-pheochromocytoma cases, the scintigram made on the 7th day proved the negative pheochromocytoma. CONCLUSION: This approach was very effective not only for finding early small pheochromocytomas and the remnants of tumors after resection, but also in diagnosing non-pheochromocytoma.

3-Iodobenzylguanidine↗
PubMed2000

Cardiovascular manifestations of pheochromocytoma.

Pheochromocytomas are rare tumors that originate in chromaffin tissue and produce their distant variant effects by secretion of catecholamines, tending to mislead the emergency physicians to a wrong diagnosis. Therefore, we analyze the clinical cardiovascular manifestations in patients with pheochromocytoma to improve the diagnostic ability of the emergency physicians. All patients presenting to the Chang Gung Memorial Hospital between January 1993 and December 1997 with a final diagnosis of pheochromocytoma had their charts reviewed. The data of 25 patients including age, sex, adrenergic stimulation presentations, electrocardiographic changes, location of the tumor, and complications were analyzed. Hypertension was the most important major manifestation and fluctuation of blood pressure drew our attention to the possibility of pheochromocytoma. Six patients had abnormal electrocardiographic ST-T segment changes. Five of them had chest pain which prompted them to undergo coronary angiography before surgery, because acute coronary syndrome (unstable angina and acute myocardial infarction) was suspected initially. However, all of them turned out to have normal coronary arteries. Right-sided pheochromocytoma was found in three of these five patients. We should maintain high index of suspicion for pheochromocytoma in patients presenting with chest pain, fluctuating blood pressure, and ischemic electrocardiogram (ECG) changes despite any typical isoenzyme changes. Pheochromocytoma should also be included in the differential diagnosis of acute coronary syndrome because acute catecholamine secretion may induce chest pain and abnormal ECG changes mimicking an ischemic episode. The right-sided pheochromocytoma may present more striking electrocardiographic abnormalities and clinical manifestations.

Adolescent↗
PubMed2002

VEGF-mediated angiogenesis of human pheochromocytomas is associated to malignancy and inhibited by anti-VEGF antibodies in experimental tumors.

BACKGROUND: Pheochromocytomas are well-vascularized tumors of the adrenal medulla. In human pheochromocytomas, angiogenesis has been associated with tumor progression. The mechanisms, however, are unknown. METHODS: Surgical specimens of benign, invasive, and metastatic human pheochromocytomas (n = 10/5/5) were immunostained for vascular endothelial growth factor (VEGF) and CD34, to determine VEGF expression and microvessel density (vascular surface density, [VSD]). In PC12-pheochromocytoma cells, VEGF messenger RNA and protein were analyzed by Northern blotting and enzyme immunoassay; biologic activity by human umbilical vein endothelial cell-proliferation assay. Inhibition of angiogenesis of PC12 xenografts by 2 neutralizing anti-VEGF antibodies (C20-pAB, M461-mAB) was evaluated by VEGF expression, VSD, and mitotic activity. RESULTS: VEGF expression and VSD were significantly higher in metastatic pheochromocytomas (VEGF 37.1 +/- 10.9% vs 20.7 +/- 9%, VSD 26.2 +/- 8 vs 13.5 +/- 3.3 1/mm). VEGF messenger RNA and protein were confirmed in PC12 cells and stimulated by nerve growth factor. Conditioned PC12 medium increased human umbilical vein endothelial cell proliferation more than 2-fold. Xentrotransplanted PC12 cells had marked VEGF expression and angiogenesis, which was inhibited by anti-VEGF antibodies (VEGF-expression by 29 and 38%, VSD by 43 and 46%, P <.05). CONCLUSION: Higher VEGF expression and microvessel density in malignant pheochromocytomas suggest VEGF-mediated angiogenesis to be related to tumor progression. Angiogenesis of PC12 xenografts is mediated by VEGF. Neutralizing anti-VEGF antibodies inhibit angiogenesis in experimental pheochromocytomas and may have potential for treating nonresectable pheochromocytomas.

Adrenal Gland Neoplasms↗
PubMed2001

Dopamine and dopa urinary excretion in patients with pheochromocytoma--diagnostic implications.

Pheochromocytoma, a potentially life-threatening disease, is a rare cause of hypertension. Most pheochromocytomas secrete excessive amounts of noradrenaline and adrenaline. It has been suggested by some authors that high circulating levels of dopamine and the catecholamine precursor dihydroxyphenylalanine (dopa) are more often associated with malignant rather than benign pheochromocytomas. Therefore the aim of this study was to evaluate urinary excretion of dopamine and dopa in patients with pheochromocytoma and to determine their role as a potential marker for malignancy of the tumour. We retrospectively analysed 120 consecutive patients (mean age 41 +/- 12 years) with histopathologically confirmed pheochromocytomas. All subjects were divided as follows: group 1 included patients with both elevated and normal dopamine urinary excretion; group 2 was characterized by increased and normal dopa urinary excretion. Dopamine urinary excretion was increased in all patients with malignant pheochromocytoma, but higher levels were also observed in some patients with a benign tumour included in group 1. Urinary excretion of dopa was in the normal range in all subjects with malignant pheochromocytoma. The results indicate that in some pheochromocytoma patients excessive dopamine excretion may point to malignant tumour, but is not a discriminating marker for malignancy in the whole studied group.

Adult↗
PubMed1994

Immunohistochemical detection of neuroblastomatous foci in composite adrenal pheochromocytoma-neuroblastoma.

To determine if immunohistochemistry might aid in the identification of neuroblastomatous foci in composite adrenal tumors, the authors analyzed two examples of composite adrenal pheochromocytoma-neuroblastoma, 18 pure pheochromocytomas, and six pure neuroblastomas using peanut agglutinin and a panel of antibodies directed against neuroendocrine and neural-associated antigens. Pure pheochromocytoma had the following immunopositivity: vimentin 14/18, chromogranin 18/18, synaptophysin 18/18, S100 protein 0/18 (tumor cells), neurofilament 14/18, J1 beta-tubulin (J1) 18/18, microtubule-associated protein-2 13/18, glial fibrillary acidic protein 13/18, and peanut agglutinin 17/18. Pure neuroblastoma reacted positively as follows: vimentin 0/6, chromogranin 5/6, synaptophysin 4/6, S100 protein 0/6 (tumor cells), neurofilament 5/6, J1 6/6, microtubule-associated protein-2 6/6, glial fibrillary acidic protein 1/6, and peanut agglutinin 6/6. Each component of both composite tumors reacted similarly to the pure neoplasms. Although the frequency of positive staining was similar for pheochromocytoma and neuroblastoma, the intensity and pattern differed for several antigens. Pheochromocytoma was diffusely positive for synaptophysin and chromogranin, whereas staining was focal and punctate in neuroblastoma. Microtubule-associated protein-2, J1, and neurofilament antibodies highlighted the fibrillar background of neuroblastoma, which pheochromocytoma lacked. Pheochromocytoma contained focal, ball-like immunoreactivity for glial fibrillary acidic protein and vimentin, which was absent in neuroblastoma. These immunohistochemical distinctions can assist the clinically important recognition of neuroblastomatous foci in composite adrenal pheochromocytoma-neuroblastoma.

Adrenal Gland Neoplasms↗
PubMed1992

Differences in left ventricular structural and functional changes between pheochromocytoma and essential hypertension. Role of elevated circulating catecholamines.

Experimental findings suggest that catecholamines increase protein synthesis and play a role in cardiac hypertrophy. We hypothesize that elevated circulating plasma catecholamines in pheochromocytoma influence cardiac structural and functional remodeling. We compared 15 patients with surgically proven pheochromocytoma and 15 with untreated essential hypertension; we matched the patients for age, sex, body surface area, and blood pressure (BP) levels. Left ventricular hypertrophy (LVH) was identified by M-mode echocardiography in six patients with pheochromocytoma and in four with essential hypertension. Among both groups there were no differences in cardiac structure, no correlation between left ventricular mass and BP, no significant differences in mitral E-F slope, no correlation between either plasma norepinephrine or plasma epinephrine levels, and no differences in the left ventricular structural indices measured. In the pheochromocytoma group, left ventricular end systolic stress and end systolic diameter were significantly lower and left ventricular percent fractional shortening was higher. Plasma norepinephrine levels were higher in the pheochromocytoma group, but did not differ among patients of that group with and without LVH. We conclude that in both pheochromocytoma and essential hypertension, only a subset of patients develop evidence of LVH, and that in pheochromocytoma, the elevation of circulating plasma catecholamines is not necessarily associated with LVH. These results indicate that factors other than catecholamines and BP determine the development of LVH in pheochromocytoma.

Adolescent↗
PubMed1993

Management of pheochromocytomas in patients with multiple endocrine neoplasia type 2 syndromes.

OBJECTIVE: The authors sought to determine the optimal surgical management of pheochromocytomas that develop in patients with multiple endocrine neoplasia (MEN) type 2 syndromes. SUMMARY BACKGROUND DATA: The performance of empirical bilateral adrenalectomy in patients with MEN 2A or MEN 2B, whether or not they have bilateral pheochromocytomas, is controversial. METHODS: The results of unilateral or bilateral adrenalectomy were studied in 58 patients (49 with MEN 2A and 9 with MEN 2B). Recurrence of disease was evaluated by measuring 24-hour urinary excretion rates of catecholamines and metabolites and by computed tomography (CT) scanning. RESULTS: The mean postoperative follow-up was 9.40 years. There was no operative mortality and malignant or extra-adrenal pheochromocytomas were not present. Twenty-three patients with a unilateral pheochromocytoma and a macroscopically normal contralateral gland underwent unilateral adrenalectomy. A pheochromocytoma developed in the remaining gland a mean of 11.87 years after the primary adrenalectomy in 12 (52%) patients. Conversely, 11 (48%) patients did not develop pheochromocytoma during a mean interval of 5.18 years. In the interval after unilateral adrenalectomy, no patient experienced hypertensive crises or other complications related to an undiagnosed pheochromocytoma. Ten (23%) of 43 patients having both adrenal glands removed (either at a single operation or sequentially) experienced at least one episode of acute adrenal insufficiency or Addisonian crisis, including one patient who died during a bout of influenza. CONCLUSIONS: Based on these data, the treatment of choice for patients with MEN 2A or MEN 2B and a unilateral pheochromocytoma is resection of only the involved gland. Substantial morbidity and significant mortality are associated with the Addisonian state after bilateral adrenalectomy.

Addison Disease↗
PubMed2000

Incidence and clinical relevance of RET proto-oncogene germline mutations in pheochromocytoma patients.

BACKGROUND: Autosomal dominant cancer syndrome--multiple endocrine neoplasia type 2 (MEN 2), may exist more often than expected in patients with pheochromocytoma. Germline mutations identified recently in MEN 2 can be revealed by genetic screening. OBJECTIVE: To evaluate the frequency of RET (rearranged during transfection) mutations in patients with pheochromocytoma. DESIGN AND METHODS: We genetically screened germline mutations in the RET proto-oncogene and clinically re-evaluated patients with pheochromocytoma. A pentagastrin test and other biochemical studies were performed in all patients. SETTING: Department of Internal Medicine and Hypertension, The Medical University of Warsaw, Warsaw, Poland and the Department of Nephrology and Hypertension, Albert Ludwigs University, Freiburg, Germany. PARTICIPANTS: Seventy seven unselected patients with pheochromocytoma (19 men, 58 women, mean age: 51.55 +/- 1.5 years; pheochromocytoma confirmed histopathologically) out of 162 diagnosed and treated in the years 1957-1998 in the Department of Internal Medicine and Hypertension in Warsaw, Poland. The other 85 patients did not respond to the written invitation. MAIN OUTCOME MEASURES: The finding of RET mutations and diagnosis of MEN 2 in patients with pheochromocytoma. RESULTS: Genetic testing revealed germline mutations in the RET proto-oncogene in six patients (7.8%). All carriers had mutation of exon 11, codon 634: TGC to CGC. In four patients with this mutation, medullary thyroid carcinoma (MIC) was diagnosed and in three cases, surgically treated. Biochemical parameters: parathormone 31.88 +/- 2.87 pg/ml, calcitonin: 0 min 0.23 +/- 0.14 ng/ml; 2 min 0.49 +/- 0.21 ng/ml; 5 min 0.48 +/- 0.21 ng/ml, metoxycatecholamines: 601.62 +/- 42.71 microg/24h, epinephrine: 1.94 +/- 0.17 microg/24h, norepinephrine 13.96 +/- 1.3 microg/24h, carcinoembryonic antigen (CEA) 9.94 +/- 4.3 ng/ml. Ambulatory blood pressure monitoring (ABPM): systolic blood pressure (SBP): 116 +/- 1.9 mmHg, diastolic blood pressure (DBP): 73.7 +/- 0.9 mmHg. Clinical, biochemical and imaging procedures did not reveal any recurrence of pheochromocytoma in the 77 patients studied. CONCLUSIONS: Patients with pheochromocytoma should be genetically screened for mutations of the RET proto-oncogene. These patients should undergo clinical screening for MEN 2. In addition, genetic studies can be useful for the screening of the families of the carriers.

Adrenal Gland Neoplasms↗
PubMed1994

Incidence of pheochromocytoma in South Galicia, Spain.

OBJECTIVES: To estimate the incidence of pheochromocytoma in the population of South Galicia (Spain) during the period 1980-1992. DESIGN: A prospective study. SETTING: The General Hospital of Vigo, a tertiary referral centre. SUBJECTS: New cases of pheochromocytoma diagnosed in the population during the years 1980-1992. The average population size was 523,934 inhabitants, (52% female, 48% male). MAIN OUTCOME MEASURES: All data were obtained from the Medical Registry, which ensures virtually complete case ascertainment for diagnosed pheochromocytoma in the population. All cases were histologically confirmed. The average annual incidence rate of pheochromocytoma was calculated. RESULTS: For the study period, 14 new cases (eight female and six male) of pheochromocytoma were diagnosed in the population of South Galicia. The average annual incidence rate in the population was 2.06 (range 0.0-3.93) per million. This incidence rate was significantly higher in the female population (2.26 vs. 1.84; P < 0.05). The mean age at diagnosis was 43 +/- 12 (range 21-65) years. Thirteen of the 14 cases were diagnosed in living patients (two discovered incidentally at operation) and one case was diagnosed at autopsy. One pheochromocytoma was located outside the adrenals. All but one tumour were benign. One patient had pheochromocytoma as part of the multiple endocrine neoplasia type IIa, and in four patients it was associated with neurofibromatosis (28.57%). Four of the 13 patients surgically treated had residual hypertension. CONCLUSIONS: The incidence of pheochromocytoma in our population is similar to that reported from other European countries. Routine screening for this disease is not recommended, but postoperative follow-up of the patients is needed. A wider study is necessary to confirm the high association with neurofibromatosis in our population.

Adrenal Gland Neoplasms↗
PubMed2004

Pheochromocytomas: detection with 11C hydroxyephedrine PET.

PURPOSE: To evaluate the accuracy of carbon 11 (11C) hydroxyephedrine (HED) positron emission tomography (PET) in the detection of pheochromocytomas. MATERIALS AND METHODS: Nineteen patients (12 women, seven men; mean age, 53 years) suspected of having pheochromocytoma were evaluated. Patients had enlarged adrenal glands at computed tomography and either increased urinary catecholamine levels (n = 18) or normal biochemistry (n = 1). Dynamic PET examination in the adrenal region was performed after injection of 800 MBq 11C HED. PET data were analyzed visually and semiquantitatively. Time-activity curves were generated for different organs. PET results were validated with histologic evaluation (n = 16) or clinical follow-up (n = 3). The diagnostic value of HED PET was evaluated by calculating the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy. RESULTS: In 12 patients, 13 pheochromocytomas were verified at surgery and histologic evaluation. All but one of the pheochromocytomas were detected with HED PET, which demonstrated elevated uptake. The rest of the patients (n = 7) did not have pheochromocytomas. In these patients, HED PET did not show any abnormal uptake in the suspicious tumors (confirmed at surgery in four patients and at clinical follow-up in three). Mean standardized uptake value of the tumors was 21.4 (range, 11.1-40.9). The time-activity curves for pheochromocytomas showed early uptake after injection, and the activity increased with the time of examination. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of HED PET in the detection of pheochromocytomas were 92% (12 of 13), 100% (seven of seven), 100% (12 of 12), 87.5% (seven of eight), and 95% (19 of 20), respectively. CONCLUSION: HED PET is useful in the detection of pheochromocytomas, providing a high level of accuracy.

Adrenal Gland Neoplasms↗
PubMed2005

Adrenocortical carcinomas and adrenal pheochromocytomas: mass and enhancement loss evaluation at delayed contrast-enhanced CT.

PURPOSE: To retrospectively measure the adrenal gland attenuation and the percentage loss of adrenal gland enhancement at delayed contrast medium-enhanced computed tomography (CT) in patients with adrenocortical carcinomas and pheochromocytomas and to compare these data with those in patients with adenomas and metastases. MATERIALS AND METHODS: The study protocol was approved by the ethics committee, which waived informed consent. Eleven patients with proved adrenocortical carcinoma, 17 with proved pheochromocytoma, 23 with adrenal adenoma, and 16 with metastasis to the adrenal gland underwent helical CT. Nonenhanced CT was followed by contrast-enhanced CT 1 minute and 10 minutes later. Attenuation and enhancement loss values were calculated. RESULTS: The mean attenuation of adenomas (8 HU +/- 18 [standard deviation]) was significantly lower than those of adrenocortical carcinomas (39 HU +/- 14), pheochromocytomas (44 HU +/- 11), and metastases (34 HU +/- 11) on nonenhanced CT scans (P < .001). Although the mean attenuation values for nonadenomas (ie, adrenocortical carcinomas, pheochromocytomas, and metastases) were significantly higher than the value for adenomas on the 1-minute contrast-enhanced CT scans (P < .001), there was more overlap in attenuation between adenomas and nonadenomas on contrast-enhanced scans than on nonenhanced scans. On the 10-minute delayed contrast-enhanced scans, the mean attenuation of adenomas (32 HU +/- 17) was significantly lower than the mean attenuations of carcinomas (72 HU +/- 15), pheochromocytomas (83 HU +/- 14), and metastases (66 HU +/- 13) (P < .001). At optimal threshold values of 50% for absolute percentage of enhancement loss and 40% for relative percentage of enhancement loss at 10 minutes, both the sensitivity and the specificity for the diagnosis of adenoma were 100% when adenomas were compared with carcinomas, pheochromocytomas, and metastases. CONCLUSION: The enhancement loss in adrenocortical carcinomas and pheochromocytomas is similar to that in adrenal metastases but significantly less than that in adrenal adenomas. The percentage change in contrast material washout is a useful adjunct to absolute CT attenuation values in differentiating adrenal adenomas from adrenocortical carcinomas and pheochromocytomas.

Adenoma↗
PubMed2004

Pheochromocytoma: an imaging chameleon.

Pheochromocytomas are rare catecholamine-secreting tumors with many clinical and imaging manifestations. They may produce overwhelming cardiovascular crises if the diagnosis is not made or if appropriate treatment is delayed. It is thus important to recognize both their characteristic and atypical imaging appearances. Pheochromocytomas are encountered, sometimes unexpectedly, across a range of imaging modalities. They are characteristically solid, hypervascular masses with high signal intensity on T2-weighted magnetic resonance (MR) images. A wide spectrum of imaging appearances is seen, however, and pheochromocytomas may mimic other adrenal lesions, both benign and malignant. They may be dark on T2-weighted MR images, in contrast to their more classic bright T2-weighted appearance. Other atypical features include fatty, hemorrhagic, cystic, and calcific changes. Pheochromocytomas may contain sufficient fat to be mistaken for an adenoma at computed tomography (CT) or MR imaging. They may also demonstrate rapid contrast material washout and be mistaken for an adenoma owing to their deenhancement profile; however, their washout pattern can be inconsistent. The appearance of pheochromocytomas at radionuclide imaging is also unpredictable. These characteristics at CT, MR imaging, and scintigraphy pose diagnostic challenges, since they allow pheochromocytomas to mimic many other adrenal masses. Pheochromocytoma is an important, often clinically occult neoplasm with devastating consequences if overlooked. Radiologists must be aware of the various forms that pheochromocytomas can assume at imaging.

Adrenal Gland Neoplasms↗
PubMed1991

Glucagon and clonidine testing in the diagnosis of pheochromocytoma.

We assessed the sensitivity and specificity of glucagon stimulation and clonidine suppression tests in the diagnosis of pheochromocytoma in 113 hypertensive patients, 39 with and 74 without the tumor. In the glucagon stimulation test, blood was sampled 2 minutes after intravenous injection of 0.28 mumol (1 mg) glucagon, and in the clonidine suppression test, blood was sampled 3 hours after administration of oral clonidine, 1.30 mumol (0.3 mg)/70 kg body wt. Baseline levels of catechols in antecubital venous blood were abnormal, with norepinephrine greater than 7.10 nmol/l (1,200 pg/m), epinephrine greater than 1.51 nmol/l (276 pg/ml), norepinephrine/dihydroxyphenylglycol (DHPG) ratio greater than 1.09, or dopa greater than 35.53 nmol/l (7,000 pg/ml), in 30 of 39 patients with pheochromocytoma (sensitivity 77%) and 1 of 74 patients without pheochromocytoma (specificity 99%). Results of the glucagon test were abnormal (norepinephrine greater than 11.83 nmol/l [2,000 pg/ml] or more than threefold increase from baseline) in 25 of 31 patients with pheochromocytoma (sensitivity 81%) and 0 of 72 patients without pheochromocytoma (specificity 100%). Results of the clonidine test were abnormal (after clonidine norepinephrine greater than 2.96 nmol/l [500 pg/ml] or less than 50% decrease from baseline) in 29 of 30 patients with pheochromocytoma (sensitivity 97%) and in 7 of 30 patients without pheochromocytoma (specificity 67%). Very high baseline levels of catechols therefore indicated the presence of pheochromocytoma, but there were several false-negative results when normal levels were obtained. The glucagon test alone was highly specific but not sensitive, and the clonidine test was highly sensitive but less specific.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Gland Neoplasms↗
PubMed2005

Clinical characteristics of pheochromocytoma patients with germline mutations in SDHD.

PURPOSE: We examined the value of SDHD mutation screening in patients presenting with apparently sporadic and familial pheochromocytoma for the identification of SDHD-related pheochromocytomas. PATIENTS AND METHODS: This retrospective study involved 126 patients with adrenal or extra-adrenal pheochromocytomas, including 24 patients with a family history of multiple endocrine neoplasia 2, von Hippel-Lindau disease, neurofibromatosis type 1, or paraganglioma (PGL). Conformation-dependent gel electrophoresis and sequence determination analysis of germline and tumor DNA were used to identify SDHD alterations. The clinical and molecular characteristics of sporadic and hereditary tumors were compared. We reviewed the literature and compared our results with those from previously published studies. RESULTS: Pathogenic germline SDHD mutations were identified in three patients: two (2.0%) of the 102 apparently sporadic pheochromocytoma patients and one patient with a family history of PGL. These patients presented with multifocal disease (two of three multifocal patients) or with a single adrenal tumor (one of 82 patients). In the literature, mutations are mostly found in patients </= 35 years of age or presenting with multifocal or extra-adrenal disease. All patients with an SDHD mutation developed extra-adrenal tumors (pheochromocytomas or PGLs) at presentation or during follow-up. CONCLUSION: SDHD gene mutations in patients presenting with apparently sporadic adrenal pheochromocytoma are rare. We recommend SDHD mutation screening for patients presenting with a family history of pheochromocytoma or PGL, multiple tumors, isolated adrenal or extra-adrenal pheochromocytomas, and age </= 35 years. Analysis of SDHD can also help to distinguish synchronous primary tumors from abdominal metastases.

Adolescent↗
PubMed2005

Differential expression of erythropoietin and its receptor in von hippel-lindau-associated and multiple endocrine neoplasia type 2-associated pheochromocytomas.

Pheochromocytoma is a neuroendocrine tumor associated with a variety of genetic disorders, which include von Hippel-Lindau disease (VHL), multiple endocrine neoplasia type 2 (MEN 2), neurofibromatosis type 1, hereditary paraganglioma, and succinate dehydrogenase gene-related tumors. Previous studies of VHL-associated and MEN 2-associated pheochromocytomas suggest morphological, biochemical, and clinical differences exist among the tumors, but the process by which they develop remains unclear. Studies in other VHL-associated tumors suggest that VHL gene deficiency causes coexpression of erythropoietin (Epo) and its receptor (Epo-R), which facilitates tumor growth. The objective of this study was to understand the different process of tumorigenesis for VHL and MEN 2-associated pheochromocytomas. Ten pheochromocytomas (VHL patients n = 5, MEN 2 patients n = 5) were examined for the presence or absence of Epo and Epo-R using Western blot, immunohistochemistry, and RT-PCR analyses. Coexpression of Epo and Epo-R was found in all five VHL-associated pheochromocytomas; in contrast, expression of Epo-R, but not Epo, was documented in all five MEN 2-associated pheochromocytomas. Expression of Epo appears to be a result of VHL gene deficiency, possibly through activation of the hypoxia inducible factor-1 pathway, whereas Epo-R is an embryonal marker whose sustained expression in both VHL- and MEN 2-associated pheochromocytomas reflects an arrest or defect in development. These findings suggest an alternative process of tumorigenesis in VHL- and MEN 2-associated pheochromocytomas and implicate Epo as a clinical biomarker to differentiate these tumors.

Adrenal Gland Neoplasms↗