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Somatostatin-like immunoactivity and biological activity is present in a human pheochromocytoma.

Somatostatin (SRIF)-like immunoreactivity (SRIF-LI) has previously been demonstrated immunohistochemically in sympathetic nerves and ganglia and in adrenal medullary cells. Studies were therefore performed to determine whether SRIF-LI was present in an adrenal pheochromocytoma. Acetic cid extracts of pheochromocytoma tissue contained high SRIF-LI concentrations (5.52 micrograms/g wet wt). On Sephadex G-75 gel filtration, the major peak of pheochromocytoma SRIF-LI coeluted with synthetic SRIF. SRIF-LI of a larger molecular size was also present in the tumor. Pheochromocytoma SRIF-LI coeluted with synthetic SRIF on reverse phase high pressure liquid chromatography. Pheochromocytoma SRIF-LI purified by high pressure liquid chromatography was equipotent to synthetic SRIF in inhibiting (Bu)2cAMP-stimulated GH release by rat pituitary cells in monolayer culture. Serum SRIF-LI was elevated in the patient before surgery and was restored toward normal after removal of the tumor. Serum levels of GH, TSH, and insulin were not obviously different before and after tumor removal. The results indicate that SRIF-LI is produced in excessive quantities by a pheochromocytoma. The immunological, chromatographic, and biological properties of the pheochromocytoma SRIF-LI suggest that it is indistinguishable from synthetic SRIF. This finding extends the list of peptides produced by pheochromocytoma and may provide an additional serum marker for the tumor in man.U

Adrenal Gland Neoplasms↗

Studies on adrenorphin in pheochromocytoma.

We studied the secretion and tissue contents of adrenorphin in human pheochromocytomas. In 17 human pheochromocytomas from 11 patients, we found a remarkably wide distribution in immunoreactive adrenorphin levels (3-7771 pg/mg tissue). Adrenomedullary pheochromocytomas contained a significantly larger amount of immunoreactive adrenorphin (2295 +/- 1092 pg/mg, mean +/- SE) than did extramedullary ones (17.8 +/- 8.4 pg/mg). Gel chromatographic studies revealed that immunoreactive adrenorphin consisted largely of material emerging at the position of synthetic adrenorphin in both pheochromocytoma and normal adrenal medulla tissue. Nicotine (10(-5) M) significantly stimulated the secretion of immunoreactive adrenorphin as well as catecholamines from cultured human pheochromocytoma cells. Adrenorphin was a more potent inhibitor of catecholamine secretion evoked by 10(-5) M nicotine than was met-enkephalin in cultured human pheochromocytoma cells. The 50% inhibitory concentrations (IC50) were 1.1 X 10(-6) and 6.5 X 10(-5) M for adrenorphin and met-enkephalin, respectively. The effect of adrenorphin was much the same as that of dynorphin-(1-13) (IC50, 1.0 X 10(-6) M) and BAM-12P (IC50, 4.5 X 10(-6) M). These results indicate the presence and secretion of adrenorphin in human pheochromocytomas. Adrenorphin may play an important role in regulating catecholamine secretion in human pheochromocytoma.

Adolescent↗

Plasma metanephrines are markers of pheochromocytoma produced by catechol-O-methyltransferase within tumors.

This study examined whether the high sensitivity of plasma free metanephrines for diagnosis of pheochromocytoma may result from production of free metanephrines within tumors. Presence in pheochromocytomas of catechol-O-methyltransferase (COMT), the enzyme responsible for conversion of catecholamines to metanephrines, was confirmed by Western blot analysis, enzyme assay, and immunohistochemistry. Western blot analysis and enzyme assay indicated that membrane-bound and not soluble COMT was the predominant form of the enzyme in pheochromocytoma. Immunohistochemistry revealed colocalization of COMT in the same chromaffin cells where catecholamines are translocated into storage vesicles by the vesicular monoamine transporter. Levels of free metanephrines in pheochromocytoma over 10,000 times higher than plasma concentrations in the same patients before removal of tumors indicated production of metanephrines within tumors. Comparisons of the production of metanephrines in patients with pheochromocytoma with production from catecholamines released or infused into the circulation indicated that more than 93% of the consistently elevated levels of circulating free metanephrines in patients with pheochromocytoma are derived from metabolism before and not after release of catecholamines into the circulation. The data indicate that the elevated plasma levels of free metanephrines in patients with pheochromocytoma are derived from catecholamines produced and metabolized within tumors. Some tumors do not secrete catecholamines, but all appear to metabolize catecholamines to free metanephrines, thus explaining the better sensitivity of plasma free metanephrines over other tests for diagnosis of pheochromocytoma.

Adult↗

Increased expression of cyclooxygenase-2 in malignant pheochromocytomas.

Pheochromocytomas are rare tumors of the adrenal medulla or the paraganglion system. There are no histological or chemical markers available that define the malignant behavior of these tumors; so far only the discovery of metastases reveals malignancy. Cyclooxygenase (Cox) is the key enzyme in conversion of arachidonic acid to PGs, and two isoforms, Cox-1 and Cox-2, have been identified. Cox-2 has been associated with carcinogenesis, and it is overexpressed in many human malignancies. We have now investigated the expression of Cox-2 in normal adrenal gland, in 92 primary pheochromocytomas and in six metastases using immunohistochemistry and Northern blot and Western blot analyses. Cox-2 protein was expressed in the adrenal cortex, whereas the medulla was negative as detected by immunohistochemistry. Interestingly, all malignant pheochromocytomas (n = 8), regardless of the primary location of the tumor, showed moderate or strong Cox-2 immunoreactivity, whereas 75% of the benign adrenal tumors (n = 36) showed no or only weak immunopositivity. The staining was negative or weak in 79% of the adrenal tumors that showed histologically suspicious features (n = 24), but had not metastasized. Most of the pheochromocytoma samples studied also expressed low levels of Cox-2 mRNA. Our data show that normal adrenal medulla does not express Cox-2 immunohistochemically. However, strong Cox-2 protein expression was found in malignant pheochromocytomas, whereas most benign tumors expressed Cox-2 only weakly. To our knowledge, this is the first report on Cox-2 expression in pheochromocytomas and enhanced expression in malignant pheochromocytomas. These findings suggest that negative or weak Cox-2 expression in pheochromocytomas favors benign diagnosis.

Adolescent↗

Inhibin/activin betaB-subunit expression in pheochromocytomas favors benign diagnosis.

Malignancy of pheochromocytomas is difficult to estimate on the basis of histopathological features. Good prognostic markers are not available. In our search for new markers to differentiate malignant pheochromocytomas from benign ones we tested the value of inhibin/activin subunit expression. Inhibins are heterodimeric glycoproteins consisting of an alpha-subunit and either a betaA- or a betaB-subunit. Activins are composed of beta-subunits only. Immunohistochemically inhibin/activin betaB-subunit was strongly positive in the normal adrenal medulla, but the cortex was negative. A striking difference was found in inhibin/activin betaB expression between benign and malignant pheochromocytomas. The majority of benign adrenal tumors (27 of 30) showed strong or moderate immunoreactivity, whereas all seven malignant tumors were negative or only weakly positive for inhibin/activin betaB-subunit. The percentage of positively staining cells varied greatly in extraadrenal pheochromocytomas and in those benign tumors that showed over 5 mitoses/10 high power fields, necrosis, or capsular or vascular invasion, here called borderline tumors. Inhibin/activin betaB messenger ribonucleic acid was also found in pheochromocytomas. However, no significant differences in messenger ribonucleic acid levels were found in various types of tumors. Weak immunohistochemical positivity for inhibin/activin betaA-subunit was detected in the adrenal cortex, but the medulla and most of the pheochromocytomas were negative. Our data show that inhibin/activin betaB-subunit is expressed in normal adrenal medullary cells. Strong staining is found in most benign adrenal pheochromocytomas, whereas malignant tumors are almost negative. This suggests that loss of inhibin/activin betaB-subunit expression in pheochromocytomas may be used as an indicator of malignant potential.

Activins↗

Analysis of the SDHD gene, the susceptibility gene for familial paraganglioma syndrome (PGL1), in pheochromocytomas.

Pheochromocytomas are neural crest-derived tumors that occur mostly sporadically, but may also be part of inherited syndromes. The molecular pathogenesis of sporadic pheochromocytomas remains unknown. Recently, the susceptibility gene for familial paraganglioma syndrome, a disorder embryologically related to pheochromocytomas, was characterized and shown to encode the small subunit of succinate dehydrogenase (SDHD), which is part of the mitochondrial complex II. This complex regulates oxygen-sensing signals. Importantly, hypoxic signals also appear to be related to the pathogenesis of pheochromocytomas associated with von Hippel-Lindau syndrome. We sequenced the entire coding region of the SDHD gene in a series of pheochromocytomas. Although we did not find mutations in the gene, we identified a new intronic single nucleotide polymorphism in 15% of the samples (g.97739A-->G). We also confirmed the existence of a sequence highly homologous to the SDHD complementary DNA in chromosome 1p34--36, a region commonly deleted in pheochromocytomas. Full analysis of this sequence revealed a heterozygous single base substitution in 70% of our samples that was also present in the germline. This sequence does not appear to be transcribed and is probably a processed pseudogene. Therefore, despite its chromosomal location, it is unlikely that this sequence is a target of loss of heterozygosity in pheochromocytomas. In conclusion, mutations of the SDHD gene are not a common event in this series of sporadic pheochromocytomas. The existence of SDHD pseudogenes should be considered when analyzing complementary DNA-based samples.

Adrenal Gland Neoplasms↗

Release of neuropeptide Y from pheochromocytomas.

To investigate the release of neuropeptide Y (NPY) from the pheochromocytomas, we studied the relationship between the plasma and tumor tissue immunoreactive (IR) NPY concentrations in 13 patients with pheochromocytoma and measured the IR-NPY concentration in plasma samples obtained by catheter from several veins (jugular veins, superior vena cava, renal veins, adrenal veins and inferior vena cava) in 2 patients with pheochromocytoma. The plasma IR-NPY concentration in 13 patients with pheochromocytoma ranged from 118 to 1460 pg/ml and the concentration in 10 of 13 patients with pheochromocytoma was above 290 pg/ml (the upper limit of normal range). The tumor tissue IR-NPY ranged from 0.025 to 95.3 micrograms/g wet tissue. Plasma IR-NPY was parallel with tumor tissue IR-NPY in 13 cases of pheochromocytoma (r = 0.76, P less than 0.01). The highest concentration of IR-NPY was found in plasma obtained from the drainage vein from a tumor among the plasma samples obtained from several veins in 2 cases of pheochromocytoma. These findings indicate that in patients with pheochromocytoma, NPY is in most cases excessively released from the tumors into the systemic circulation and plasma IR-NPY in the periphery is increased.

Adrenal Gland Neoplasms↗

Expression of mRNA coding for four catecholamine-synthesizing enzymes in human adrenal pheochromocytomas.

OBJECTIVE: To understand the molecular mechanisms by which catecholamine synthesis is controlled in pheochromocytomas--tumors that synthesize and release catecholamines, which are related to various clinical manifestations of the condition. METHODS: We measured the concentrations of mRNA coding for the catecholamine-synthesizing enzymes tyrosine hydroxylase, aromatic L-amino acid decarboxylase (AADC), dopamine beta-hydroxylase (DBH) and phenylethanolamine N-methyl transferase (PNMT) and for the catecholamine contents in 12 pheochromocytomas and 12 normal adrenal medullas. RESULTS: The mean content of total catecholamine and the beta-actin mRNA expression in the pheochromocytomas were almost the same as those in the normal adrenal medullas. However, the tyrosine hydroxylase, AADC and DBH mRNA concentrations in the pheochromocytomas were greater than those of the normal adrenal medullas. Conversely, the PNMT mRNA concentration in the pheochromocytomas was lower than that in the normal adrenal medullas. These differences are responsible for the difference in the proportions of catecholamines between pheochromocytomas and normal adrenal medullas. The constitutive expression of the catecholamine-synthesizing enzyme mRNAs varied in magnitude among the pheochromocytomas, and the tyrosine hydroxylase mRNA expressions correlated with the contents of total catecholamine in the tumors (r=0.964, P<0.0001). CONCLUSIONS: These findings indicate that catecholamine production in pheochromocytomas is primarily controlled by the level of gene expression.

Adrenal Gland Neoplasms↗

Pheochromocytoma in multiple endocrine neoplasia type 2: a prospective study.

OBJECTIVE: The aim of this prospective study is to update our knowledge of the chronology of pheochromocytoma occurrence in multiple endocrine neoplasia type 2 (MEN 2), and to better manage MEN 2 patients after the genetic diagnosis. DESIGN: Eighty-seven non-index gene carrier MEN 2 patients were included in this prospective study: 84 patients with MEN 2A (from 52 families) and 3 with MEN 2B (from 3 families). METHODS: Medullary thyroid carcinoma (MTC) was diagnosed by measuring plasma calcitonin in basal conditions or after pentagastrin stimulation. The search for pheochromocytoma consisted of clinical evaluation, 24 h determination of urinary catecholamines and adrenal imaging. The mean age at genetic diagnosis of MEN 2 was 14.0+/-7.0 years, the mean duration for the follow-up was 7.6+/-2.8 years. RESULTS: All 87 patients had a MTC detected at the same time as the genetic diagnosis was made. Urinary catecholamine measurements led to the diagnosis of pheochromocytoma and a combination of imaging techniques enabled the correct localization of both unilateral or bilateral adrenal involvement. Pheochromocytoma was detected simultaneously with MTC in only seven patients, and seven others were detected throughout the follow-up. Of the 14 patients with pheochromocytoma, 11 had bilateral involvement: nine were initially bilateral and two became so during follow-up. CONCLUSION: This study demonstrates that in MEN 2, MTC is the lesion which appears earliest. Pheochromocytoma develops later during the evolution of the disease, and necessitates regular clinical and biological monitoring throughout follow-up. Determination of urinary and/or plasma catecholamines and metanephrines should be performed to detect pheochromocytoma. Imaging techniques lead to the detection of both unilateral and bilateral pheochromocytoma, thus making video-assisted laparoscopic adrenalectomy possible.

Adolescent↗

Overexpression of the insulin-like growth factor I receptor in human pheochromocytomas.

In order to determine the role of the IGF-I receptor (IGF-IR) in human pheochromocytomas we have compared the expression of the IGF-IR in normal tissues and in pheochromocytomas with regard to the IGF-IR mRNA levels and ligand binding. By semiquantitative reverse transcription polymerase chain reaction (RT-PCR), the mRNA of the IGF-IR could be detected in all samples of normal adrenomedullary cells (n = 13) and pheochromocytomas (n = 16). However, pheochromocytomas exhibited 2.8-fold higher mean IGF-IR mRNA levels than normal adrenomedullary cells (2.8 +/- 0.5 x 10(5) molecules/mug RNA vs 7.8 +/- 1.2 x 10(5) molecules/mug RNA; P < 0.001). This overexpression of the IGF-IR in pheochromocytomas could be confirmed at the protein level by binding studies. Radioligand assays and Scatchard analysis revealed a single class of high affinity IGF-IR binding sites with a similar dissociation constant (Kd: 0.32 +/- 0.1 nmol/l vs 0.22 +/- 0.08 nmol/l) for both normal adrenomedullary cells and pheochromocytomas. However, specific 125I-labeled IGF-I binding and the calculated receptor concentration were significantly elevated in pheochromocytomas as compared with normal adrenomedullary cells (58.3 +/- 5 vs 24.3 +/- 12 nmol/kg protein; P < 0.05). In summary, our results demonstrate significant overexpression of the IGF-IR in human pheochromocytomas. This suggests a possible role of the IGF system in the pathogenesis of adrenal neoplasia and thus IGF-IR may be a target for future therapeutic approaches.

Adrenal Medulla↗

[Coexisting pheochromocytoma and renal artery stenosis].

OBJECTIVE: To improve the diagnosis of coexisting pheochromocytoma and renal artery stenosis. METHOD: Four patients with coexisting pheochromocytoma and renal artery stenosis were treated. RESULT: After removal of the pheochromocytoma, the blood pressure became normal in two patients combined with resection of kidney with renal artery stenosis, and one patient with local adhesion loosened. The hypertension, however, persisted in another patient after the resection of pheochromocytoma even though the long segment of renal artery stenosis was relieved. CONCLUSION: After pheochromocytoma was diagnosed with its known position, coexisting renal artery stenosis should be suspected according to one of the following conditions: (1) Vascular murmurs are noted at the area of the upper abdomen or back; (2) One of the kidneys becomes less sized; (3) Using the inhibitor of receptor alpha only has no effect lowering blood pressure and it is necessary to add the inhibitor of angiotension; (4) Postoperative hypertension does not resolve when no remaining pheochromocytoma is present. the renal artery stenosis can be reversed after both removal of pheochromocytoma and loosening of adhesion in case of stenosis due to the pressure of the tumor and adhesion caused renal artery angling and local stricture. Extensive stenosis or closure, however, can not be corrected with severe atrophy of renal parenchyma due to pheochromocytoma, and the resection of kidney should be indicated.

Adolescent↗

Modern imaging methods and preoperative management of pheochromocytoma: review of the literature and case report.

OBJECTIVES: To discuss the modern imaging techniques and preoperative management of pheochromocytoma and to report on one additional case. METHODS: A 66-year-old male with an incidentally discovered left adrenal mass is described. The adrenal medulla strongly accumulate 131 I-metaiodobenzylguanidine (MIBG). The patient underwent left adrenalectomy after preoperative therapy with alpha and beta-blockers. The recent literature on pheochromocytoma modern imaging techniques and preoperative management is reviewed. RESULTS: MIBG scintigraphy diagnosed a benign functioning adrenal pheochromocytoma, allowing preoperative medical management. Postoperative workup was unremarkable. Diagnosis of pheochromocytoma was confirmed by immunohistopathology. At 18 months follow-up, the patient is alive and disease-free. CONCLUSIONS: Incidentally discovered adrenal masses have to be investigated to detect malignancy and subtle hormonal overproduction. MIBG scintigraphy has a high specificity (100%) in detecting pheochromocytoma, metastasis, surgical residual tumor, local relapse and other adrenal crest tumors. Positive results of octreotide scintigraphy in detecting malignant pheochromocytoma have been reported. Currently, pheochromocytoma removal is a safe operation with mortality rates ranging from 0 to less than 3%. Preoperative alpha adrenergic blockage with phenoxybenzamine or prazosin is important in decreasing the operative risk. Beta-blockers may be necessary for cardiac arrhythmia. Intraoperative invasive monitoring of hemodynamic variables may be both diagnostic and therapeutic of inadequate preoperative management. Lifelong follow-up for patients with pheochromocytoma is important.

3-Iodobenzylguanidine↗

Enkephalin degradating enzymes in pheochromocytoma patients.

Adrenal gland as a major source of enkephalins on the periphery can be affected by a rare adrenal gland tumor, adrenal pheochromocytoma. It has been demonstrated that this tumor might be associated with altered concentration of enkephalin-like peptides. The effect of these peptides can be either prolonged or abbreviated by two neutrophil membrane bound enzymes; aminopeptidase N (APN) and neutral endopeptidase (NEP). We assumed that altered enkephalin level in pheochromocytoma patients (but not in patients with non-functional adenomas or tumors of different origin) might result in differently regulated APN and/or NEP activity. We measured APN and NEP activity on surface of neutrophils, level of lipid peroxidation (LPO) in plasma and enkephalin concentration in plasma in patients with pheochromocytomas, non-functional adenomas, malignant renal tumors and healthy controls. Catheholamines and vanyllmandelic acid (VMA) were measured in 24-h urine of pheochromocytoma patients. NEP and APN activity on neutrophils from all pheochromocytoma patients was significantly increased as compared with healthy controls, non-functional adenomas and malignant renal tumors. In all pheochromocytoma patients NEP activity was reduced almost to the control level after surgery. At the same time APN activity was in some patients up- and in others down-regulated. In comparison, elevated levels of cateholamines and VMA were found after multiple determinations in 6 out of 10 pheochromocytoma patients. Although preliminary, this study has shown specifically and consistently up-regulated NEP activity on neutrophils from pheochromocytoma patients, and uniformly decreased NEP activity in these patients after adrenalectomy.

Adenoma↗

[Pheochromocytoma, first manifestation of Von Hippel-Lindau disease: a possibility to be considered].

Von Hippel-Lindau (VHL) disorder is an autosomal dominant disease characterized by the almost constant development of hemangioblastomas in the central nervous system (cerebellum, spinal cord and retina). In addition, various types of tumors including renal cell carcinomas, pancreatic cysts and pheochromocytomas are frequently observed in VHL gene carriers. Linkage of the VHL locus to the RAF-1 oncogene on the short arm of chromosome 3 (3p25-26) has been recently reported. Pheochromocytoma is of particular interest because of the risk of inaugural malignant hypertensive crisis but especially because of a great degree of interfamily variability (from 0 to 92% of affected members in previously reported large kindreds). We have studied a French series of 25 pheochromocytoma (11 males, 14 females) in VHL affected patients. Twenty pheochromocytoma (80%) occurred in a familial context, whereas 5 (20%) were consistent with "apparent sporadic cases". The mean age at pheochromocytoma diagnosis was 27 years (5-55 years). Bilateral tumours have been documented in 13 cases (52%). The prevalence of pheochromocytoma revealing VHL was 14 out 25 (56%). In these cases, VHL diagnosis was considered up to 25 years later. In 6 cases (2 deceased) pheochromocytoma was the only manifestation of VHL. Thus, search for VHL must be systematic in the presence of pheochromocytoma, in the interest of the patients themselves and of potential at-risk family members (prevention of hypertensive crisis linked to latent tumours). Basic check-up (neurological and somatic examination, ophthalmoscopy, familial inquiry) may be completed with cerebral CT scan or MRI and abdominal ultrasonography followed, if positive or doubtful, by abdominal MRI or selective angiography.

Adolescent↗

[Clinical analysis of 25 patients with bilateral pheochromocytomas].

OBJECTIVE: Bilateral pheochromocytomas are rare diseases. The purpose of this retrospective study was to elucidate the clinical characteristics of patients with bilateral pheochromocytomas. METHODS: We analyze the clinical data of 25 patients with bilateral pheochromocytomas who were treated at Peking Union Medical College Hospital between 1952 and 2004. RESULTS: The average age at diagnosis was (32 +/- 14) years. 19 cases (76%) were familiar type, and among the 19 cases, 13 cases were multiple endocrine neoplasia (MEN), 5 cases von Hippel-Lindau (vHL) disease and 1 case of isolated familial pheochromocytomas. In the 25 patients, bilateral pheochromocytomas were discovered at the same time in 88%, and multiple tumors existed in at least one side of the adrenal gland in 56%. 50% of cases recurred after resection of pheochromocytomas. CONCLUSIONS: Hereditary syndromes should be screened when pheochromocytoma is bilateral, and the patients' family members also should be screened for hereditary syndromes. During operation for bilateral adrenal pheochromocytoma, multiple tumors in one side should be considered. Long-term follow-up is necessary because recurrence may develop many years after operation.

Adolescent↗

[Analysis of morphology of adrenal pheochromocytoma as regards their potential malignancy].

BACKGROUND: Adrenal pheochromocytoma are diagnosed the most often in patients with arterial hypertension or with thyroid medullar cancer and suspicion of MEN II syndromes. The aim of the study is to analyse the morphology of pheochromocytomas on the basis of Pheochromocytoma of the Adrenal Gland Scaled Score (PASS) in order to estimate their potential malignancy. MATERIAL AND METHODS: Forty tumours were subjected to analysis. Mean patients age was 45.2+/-13.4 years. The diagnosis of pheochromocytoma was establish before surgery in 87.5%. 12.5% of patients were referred to surgery on the basis of tumour diameter (range 70 to 102 mm). In 20.0% of patients MEN II syndromes were diagnosed. RESULTS: In pathological examination benign pheochromo-cytoma was diagnosed in 39 presented patients. In 1 cases malignant form of pheochromocytoma was diagnosed on the basis of lymph nodes metastases. Number of points in PASS was >or=4 in 9 of 40 tumours (22.5%). Among 35 patients operated on more than 12 months ago 2 patients died: 1 patient with malignant pheochromocytoma (PASS=8 points) and 1 patient with MEN IIA syndrome (due to disseminated thyroid medullar cancer). In remaining 7 observed patients with PASS>or=4 points neither recurrence nor metastases were diagnosed within the period of observation (13-90 months). In 1 out of patients with PASS<4 points a local recurrence was surgically removed 82 months after primary operation. CONCLUSION: Analysis of pheochromocytoma in PASS is only of rough character and does not allow for clear-cut histological diagnosis of benign and malignant tumours. The only unquestionable criterion of pheochromocytoma's malignancy remain metastases.

Adrenal Gland Neoplasms↗

[Experience with 33 operations for pheochromocytoma].

The authors submit experience with 33 operations of pheochromocytomas in 29 patients, incl. 5 children under 15 years (15%) and 5 adolescents aged 16 to 23 years (15%). Of 33 pheochromocytomas 32 were benign (23 adrenal, 9 extra-adrenal) and 1 malignant pheochromoblastoma. In 4 patients there were duplicit pheochromocytomas and in one triplicit (both adrenals and an extraadrenal pheochromocytoma). Five patients developed relapses or new pheochromocytomas in the course of 4-16 years after the previous operation. The only serious peroperative and post-operative complication with a fatal outcome was in 1957 in a 17-year-old girl with bilateral pheochromocytoma of the adrenal medulla, where the left one was diagnosed and extirpated in 1953, while the other one was not diagnosed intra vitam. The authors evaluate also the long-term results of their patients who survive 3-25 years after operation. Three died some time after operation (pheochromoblastoma, 2X IM), two were recently re-operated on account of new pheochromocytomas which developed 11-16 years after the first operation. Patients after operation of pheochromocytomas should be regularly checked and dispensarized throughout life.

Adolescent↗

Cardiomyopathy in a rat model of pheochromocytoma. Morphological and functional alterations.

To investigate the cardiac muscle damage observed in pheochromocytoma, New England Deaconness Hospital rats were implanted subcutaneously with a transplantable pheochromocytoma. The tumor was evident 4 weeks after transplantation. Approximately 5-6 weeks after transplant, systolic blood pressure was significantly increased in tumor-bearing animals (183 +/- 13 vs 119 +/- 7 in controls). At this time a cardiomyopathy with the following features was apparent in the tumor-bearing animals: multifocal lesions of enhanced interstitial and replacement fibrosis; granularity of the cytoplasm and contraction band necrosis; and mixed inflammatory infiltrates. Using a morphological scoring system from 0 (no cardiac damage) to 3 (complete involvement of the ventricular cross section studied), the pheochromocytoma animals had a cardiomyopathy score of 1.8 +/- 0.1, which is significantly greater than that found in age- and sex-matched controls: 0.4 +/- 0.1, p less than .001. A significant increase in the wet heart weights (1.28 +/- 0.07 vs. 1.12 +/- 0.04 in controls) was also observed in these animals, indicating the possibility of cardiac hypertrophy in the pheochromocytoma rats. There was a marked decrease in sensitivity to isoproterenol in isolated, electrically driven left atrial strips from pheochromocytoma rats. Isoproterenol's EC50 increased eightfold from 1.5 +/- 0.6 x 10(-8) M in controls to 1.3 +/- 0.4 x 10(-7) M in left atrial strips from the pheochromocytoma rats. However, there was no difference in maximal contractile response to isoproterenol in either the left atrial strips or in right or left ventricular papillary muscle strips. Also, there was no change in responsiveness of either left atrial or right ventricular muscle strips from pheochromocytoma hearts to contraction induced by 3.75 mM calcium chloride. However, the contractile response to calcium was enhanced in left ventricular papillary muscle from tumor-bearing animals (808 +/- 195 vs 372 +/- 101 mg tension in controls, p less than 0.05). These results demonstrate a catecholamine-induced cardiomyopathy in hearts from pheochromocytoma-bearing rats. Furthermore, the results demonstrate a functional beta-adrenergic receptor desensitization in isolated left atrial strips from tumor-bearing rats, whereas maximal contraction of heart muscle, induced by either isoproterenol or calcium chloride, remains intact.

Animals↗