New insights in the genetics of adrenocortical tumors, pheochromocytomas and paragangliomas

Li-Fraumeni Syndrome With Six Primary Tumors-Case Report

Li-Fraumeni syndrome (LFS) is a cancer predisposition syndrome associated with a high, lifetime risk of a broad spectrum of cancers caused by pathogenic germline TP53 mutations. Numerous different germline TP53 mutations have been associated with LFS, which has an exceptionally diverse clinical spectrum in terms of tumor type and age of onset. Our patient has developed six asynchronous tumors to date: a phyllode tumor of the breast, a pheochromocytoma, a rosette-forming glioneuronal tumor (RGNT), an adrenocortical carcinoma (ACC), a ductal carcinoma of the breast, and a thymoma. The occurrence of such a number of rare tumors is sporadic even among in the population of patients living with cancer predisposition syndromes. In this instance, the omission of pretest genetic counseling and thorough family tree analysis prior to selecting the test led to the oversight of an underlying TP53 likely pathogenic mutation (classified as Class 4). This emphasizes the necessity for such counseling to prevent overlooking crucial genetic information. Neglecting this step could have had profound implications on the patient's treatment, particularly considering the early onset and occurrence of multiple tumors, which typically raise suspicion of a hereditary component. The implications for family members must be considered.

[New aspects of tumor pathology of the adrenal glands]

In daily routine pathology of the adrenal glands three tumor entities are important: adrenocortical tumors, adrenomedullary tumors and metastases. The differentiation of these three main tumor types can often be difficult structurally but immunostaining enables a definite diagnosis in nearly all cases. Adrenocortical tumors are positive for steroidogenic factor 1 and melan-A and always negative for chromogranin A whereas adrenomedullary tumors express chromogranin A but never keratin. A broad spectrum of antibodies is available for the identification of metastases and even the rare epithelioid angiosarcomas. For adrenocortical tumors, adenomas and carcinomas can be differentiated using three scoring systems and the Ki-67 index in adenomas should not exceed 3%. Using scoring systems and the Ki-67 index approximately 90% of cortical tumors can be differentiated into benign or malignant tumors. For pheochromocytomas two scoring systems are used for differentiating benign and malignant tumors but the results are less dependable.

Thymic neuroendocrine tumors (paraganglioma and carcinoid tumors): a comparative immunohistochemical study of 46 cases

Twenty-two paragangliomas from different anatomical sites and 24 thymic neuroendocrine carcinomas (carcinoid tumors) were analyzed for traditional and novel immunohistochemical markers. In the paraganglioma group, there were 8 men and 14 women between the ages of 23 and 79 years (mean, 46 years). Their symptoms depended on the location of the tumor and included neck swelling and Horner syndrome for neck tumors, whereas abdominal and chest pain was present in tumors of the abdomen and mediastinum, respectively. One patient had Carney triad. In the carcinoid group, the patients were 20 men and 4 women between the ages of 25 and 78 years (mean, 48 years). These patients were symptomatic with chest pain, shortness of breath, and dyspnea. One patient presented with multiple endocrine neoplasia syndrome. Complete surgical resection was accomplished in all patients. The 46 neuroendocrine tumors were evaluated for GATA-3, pancytokeratin, thryoid transcription factor 1 (TTF-1), napsin A, chromogranin A, and synaptophysin. All paragangliomas were universally positive for chromogranin A and synaptophysin, but negative for pancytokeratin, TTF-1, and napsin A. GATA-3 was expressed in 12 (55%) of 22 tumors. The thymic neuroendocrine carcinomas (carcinoid tumors) were universally positive for pancytokeratin, but negative for GATA-3 and napsin A. Chromogranin A and synaptophysin were expressed in 92% and 88% of cases, respectively, and TTF-1 in 4 (17%) of 24 cases. Based on these results, we recommend that the workup of neuroendocrine tumors should include not only the conventional neuroendocrine markers and pancytokeratin but also other markers such as GATA-3 and TTF-1 in order to arrive at a better interpretation.

Carney complex presenting with a unilateral adrenocortical nodule: a case report

INTRODUCTION

Carney complex is an autosomal dominant syndrome with multiple neoplasms in different sites, including myxomas, endocrine tumors and lentigines lesions. To the best of our knowledge, this is the first report of Carney complex presenting with a unilateral adrenal adenoma associated with a pituitary incidentaloma.

CASE PRESENTATION

A 27-year-old Iranian woman was referred to our endocrinology clinic with amenorrhea and hirsutism, further confirming a diagnosis of adrenocorticotropic hormone-independent Cushing's syndrome. The cause was believed to be a right adrenocortical adenoma based on a computed tomography scan. Our patient underwent a right laparoscopic adrenalectomy and pathological examination revealed pigmented micronodular adrenal hyperplasia. Pituitary magnetic resonance imaging also documented a microadenoma that was considered to be an incidentaloma based on normal pituitary function tests. Recurrence of hypercortisolism led to a left laparoscopic adrenalectomy, providing further evidence for the diagnosis of primary pigmented nodular adrenocortical disease. Carney complex was established in light of her history of cardiac myxomas.

CONCLUSION

We present what we believe to be the first case of Carney complex presenting with a unilateral adrenocortical adenoma in association with a pituitary incidentaloma. Although primary pigmented nodular adrenocortical disease is rare as a component of Carney complex, it should be considered in the differential diagnosis of Cushing's syndrome. Rarely, adrenal and pituitary imaging can be misleading.

Mesenteric paraganglioma: Report of a case

We report a rare case of paraganglioma that developed in the mesentery of terminal ileum. A 78-year-old woman complained of right-sided abdominal pain. Abdominal computed tomography revealed a solid heterogeneously enhanced mass in the right lower abdomen. The tumor was laparoscopically excised. The mesenteric tumor was well circumscribed, ovoid, and encapsulated and measured 3 cm × 1.5 cm × 1.5 cm. Histological examination showed a cellular neoplasm comprised of nests and groups of tumor cells separated by fibrovascular connective tissue, giving a characteristic nested Zellballen pattern. Immunohistochemically, the tumor cells were positive for chromogranin, synaptophysin, CD56, and vimentin and negative for cytokeratins, SMA, CD34, CD117/c-kit and S100. On the basis of histologic and immunohistochemical features, a diagnosis of mesenteric paraganglioma was made. The operative and postoperative courses were unremarkable, and the patient was discharged on postoperative day 7. She was doing well 1 year after the surgery with no signs of recurrence. Extra-adrenal paragangliomas most commonly develop adjacent to the aorta, particularly the area corresponding to the organ of Zuckerkandl. Mesenteric paraganglioma, as in our case, is extremely rare; only 11 cases have been reported in the literature. We herein discuss the clinical findings of these cases.

Adrenal cortical tumors, pheochromocytomas and paragangliomas

Distinguishing adrenal cortical adenomas from carcinomas may be a difficult diagnostic problem. The criteria of Weiss are very useful because of their reliance on histologic features. From a practical perspective, the most useful criteria to separate adenomas from carcinomas include tumor size, presence of necrosis and mitotic activity including atypical mitoses. Adrenal cortical neoplasms in pediatric patients are more difficult to diagnose and to separate adenomas from carcinomas. The diagnosis of pediatric adrenal cortical carcinoma requires a higher tumor weight, larger tumor size and more mitoses compared with carcinomas in adults. Pheochromocytomas are chromaffin-derived tumors that develop in the adrenal gland. Paragangliomas are tumors arising from paraganglia that are distributed along the parasympathetic nerves and sympathetic chain. Positive staining for chromogranin and synaptophysin is present in the chief cells, whereas the sustentacular cells are positive for S100 protein. Hereditary conditions associated with pheochromocytomas include multiple endocrine neoplasia 2A and 2B, Von Hippel-Lindau disease and neurofibromatosis I. Hereditary paraganglioma syndromes with mutations of SDHB, SDHC and SDHD are associated with paragangliomas and some pheochromocytomas.

Predictive factors for malignant pheochromocytoma: analysis of 136 patients

PURPOSE

We evaluated the clinical characteristic, tumor feature and immunohistochemistry factors predicting malignant pheochromocytoma.

MATERIALS AND METHODS

Between January 1999 and December 2008 we retrospectively reviewed the records of 136 patients with pheochromocytoma at Ruijin Hospital. We compared clinical characteristics (age, gender, symptoms and biochemical analysis), tumor features (site, weight and diameter) and the expression of 3 angiogenesis/metastasis related genes (VEGF, Cox-2 and MVD) by immunohistochemical analysis of benign vs malignant pheochromocytomas.

RESULTS

Of the 136 patients 105 (77%) had benign and 31 (23%) had malignant pheochromocytoma. Malignant tumors were larger and heavier than benign tumors, and accompanied by higher plasma metanephrine secretion (each p <0.001). Mean tumor catecholamine and preoperative 24-hour urinary metanephrine or normetanephrine were obviously higher in malignant than in benign tumors (p <0.001). Also, 25 malignant tumors (81%) were immunopositive for VEGF while only 24 benign tumors (23%) showed this characteristic (p <0.001). Microvessel density and the rate of positive staining for Cox-2 protein in malignant samples were higher than in benign samples (p <0.001).

CONCLUSIONS

Several promising predictive parameters are currently available to distinguish benign from malignant pheochromocytoma. Large (5 cm or greater) or heavy (250 gm or greater) tumors, multifocal and extra-adrenal tumors, early onset postoperative hypertension and higher plasma or urine metadrenaline are high risk factors predictive of malignant pheochromocytoma. Also, expression of the 3 angiogenesis or metastasis related genes VEGF, Cox-2 and MVD helps determine the diagnosis of malignancy and suggests strict followup.

Hereditary paragangliomas

Paragangliomas (PGL) and pheochromocytomas (PCC) are rare, usually benign tumors that originate from the neuroendocrine tissue along the paravertebral axis. Up to 35% of these tumors may be hereditary; they are associated with germline mutations in genes encoding subunits of the succinate dehydrogenase (SDH) enzyme complex in the context of the familial PGL syndromes, PGL1, 3 and 4 caused by mutations in the SDHD,SDHC and SDHB genes, respectively. Another familial PGL syndrome, PGL2, is caused by mutations in SDHAF2/SDH5, which encodes for a molecule that is an accessory to the function of the SDH enzyme and its SDHA subunit. Less frequently, mutations in the genes responsible for Von Hippel Lindau disease (VHL), multiple endocrine neoplasia type 2 (MEN2), and neurofibromatosis type 1 (NF1) are also found in patients with hereditary PGL and PCC. Recently mutations were found in the SDHA subunit in a limited number of patients with PGL and/or PCC. The SDHB, SDHC and SDHD gene mutations (but not SDHA) can also be found in patients with PGL and/or PCC and gastrointestinal stromal tumors (GISTs), also known as the Carney-Stratakis syndrome; SDHB mutations, in particular, may also predispose to thyroid and renal cancer, and possibly other tumors. A new gene was recently found to predispose to PGL and/or PCC when mutated is TMEM127. In this text, we provide an overview of the genetics of PGLs and related conditions with an emphasis on genetic risk assessment, prevention, and prognosis.

Clinicopathological analysis of paraganglioma with literature review

AIM: To investigate the 152 cases of paragangliomas resected over the past 32 years in West China Hospital clinicopathologically.

METHODS: All cases of paragangliomas diagnosed at the Department of Gastrointestinal Surgery and Department of Pathology, West China Hospital, China were reviewed. The pathological documents were supplied by the Department of Pathology, West China Hospital, and other necessary data were extracted from the hospital records. The statistical analyses were performed by survival analysis (Kaplan-Meier method), descriptive statistical analyses and χ² analysis.

RESULTS: The neuroendocrine marker vimentin was found to be selectively expressed in the benign tumors, and there were significant differences in the expression of those markers in both benign and malignant tumors. The survival analysis revealed that survival correlated significantly with the malignancy, metastasis and nodal status.

CONCLUSION: Vimentin may be useful in the differential diagnosis between malignant and benign tumors. The difference in the expression of this marker in the tumors could be a clue to the future clinical diagnosis. The malignancy, metastasis and the nodal status may predict the prognosis of this disease.

[Sporadic adrenocortical tumors: genetics and perspectives for the pathologist]

Most adrenocortical tumors are benign; adrenocortical carcinomas are rare but their prognosis is poor and few therapeutic options are available. In most adrenocortical tumors, the morphological approach provides enough elements to establish the differential diagnosis between a benign and a malignant tumor but in few cases, it is insufficient. Moreover, morphology is limited for predicting prognosis of adrenocortical carcinomas. These observations led to development of other approaches, in particular immunohistochemical and genetic approaches. The comprehension of the genetic syndromes associated with adrenocortical tumors led to progress in the identification of genetic abnormalities involved in sporadic adrenocortical tumorigenesis. Thus, in sporadic adrenocortical tumorigenesis, IGF-II overexpression and cyclin E overproduction have been associated with 11p15 alterations which are observed in Bethwith-Wiedemann syndrome and TP53 inactivating mutations and 17p13 locus abnormalities which are observed in Li-Fraumeni syndrome. Activation of the Wnt/ss-catenin signaling pathway which is observed in familial adenomatous polyposis has been found in adrenocortical adenomas and carcinomas associated to mutations of CTNNB1, the gene coding ss-catenin, suggesting a central role for this pathway in adrenocortical tumorigenesis. These genetics findings already have had repercussions for patients via the development of molecular markers for diagnosis and prognosis; in the future they should be helpful in the development of new therapeutics.

Development of differential diagnosis for benign and malignant pheochromocytomas

Unlike common malignant tumors, malignant pheochromocytomas cannot be definitely diagnosed using histological features. This unique nature of pheochromocytomas provides a valuable model that may promote the investigation of the mechanism of other common malignant tumors where similar frameworks are not available. Studies on malignant pheochromocytomas should benefit not only the individuals with pheochromocytomas but those with other tumors. A review on the development of differentiating diagnosis between malignant and benign pheochromocytomas in imaging studies, biological fluid examinations, pathological examinations, molecular markers and genome studies, was updated in the hopes of guiding the next studies of pheochromcytomas.

Pararectal paraganglioma

Paragangliomas are neoplasms that arise from neural crest cells and histologically resemble their adrenal counterpart, the phaeochromocytoma. The majority of extra-adrenal tumours develop within the abdomen and are associated with the coeliac, superior and inferior mesenteric ganglia, which run parallel to the aorta. The organ of Zuckerkandl origin is most common. Pararectal paragangliomas are extremely rare. This case report presents ultrasound, magnetic resonance and histological features of such a case.

Familial nonsyndromic pheochromocytoma

Judging from recent data, heritable forms account for 30-40% of pheochromocytomas. The molecular basis for the familial pheochromocytoma has been largely elucidated and the role of germline mutation of the VHL, RET, SDHB, and SDHD genes has been established. However, on genotyping a group of 172 sporadic or familial pheochromocytomas, we characterized four unrelated probands with familial pheochromocytomas without any sequence variants of RET (exons 8, 10, 11, 13, 14, 15, and 16) or the entire coding sequence of VHL, SDHB, SDHC, SDHD, and EGLN3 (exon-intron boundaries included). The proband of family 1 is a man who had a bilateral pheochromocytoma at the age of 32 and a local recurrence at the age of 48 years. His brother died of malignant pheochromocytoma and his nephew died suddenly of an undiagnosed pheochromocytoma. The proband of family 2 is a female who had a 5-cm benign adrenal pheochromocytoma at the age of 34 years, while her cousin (maternal branch) had a monolateral pheochromocytoma at the age of 42 years. No other tumors had been reported in either family. The proband of family 3 is a female who had a bilateral pheochromocytoma at the age of 66 years. Her sister had a bilateral pheochromocytoma and breast cancer at the age of 54 years. Several other tumors were recorded in this family, including laryngeal cancer, leukemia, and a case of medullary thyroid carcinoma (MTC) in one brother. MTC was naturally ruled out in the proband and her sister. In family 4, the proband was a female who had a bilateral pheochromocytoma at the age of 46 years and a local recurrence a few years later, with liver metastases from the pheochromocytoma. Her brother had a monolateral benign pheochromocytoma. The proband also had a melanoma and bilateral renal cysts. This case revealed a VHL sequence variant IVS2+43 A>G, which was also found in one other unrelated sporadic pheochromocytoma. VHL mRNA integrity is currently being evaluated. The proband had no cerebellar or spinal NMR findings or retinal alterations. In family 5, the proband was a female who had a right adrenal pheochromocytoma at the age of 50 years and a breast cancer at 49 years of age. Her mother had had a right adrenal pheochromocytoma at 61 years of age. Although other molecular mechanisms, such as particular variants in untranslated regions or partial gene deletions, cannot be ruled out, we think finding families with nonsyndromic pheochromocytoma without any RET, VHL, SDHB, SDHC, SDHD, or EGLN3 mutation may argue in favor of the presence of other pheochromocytoma susceptibility genes.

Development of novel tools for the diagnosis and prognosis of pheochromocytoma using peptide marker immunoassay and gene expression profiling approaches

Pheochromocytomas (PHEOs) are rare catecholamine-producing neoplasias that arise from chromaffin cells of the adrenal medulla or from extra-adrenal locations. These neuroendocrine tumors are usually benign, but may also present as or develop into a malignancy. There are currently no means to predict or to cure malignant tumors which have a poor prognosis. We have recently validated several assays for the measurement of peptides derived from chromogranin A (CgA) and secretogranin II (SgII) in order to determine whether these secreted neuroendocrine products could provide useful, complementary markers for the diagnosis and prognosis of PHEOs. Both the CgA-derived peptide WE14 and the SgII-derived peptide EM66 proved to be sensitive circulating markers for the diagnosis of PHEO. In addition, much higher EM66 levels were measured in benign than in malignant tumoral tissues, suggesting that this peptide could represent a valuable tool for the prognosis of PHEO. We have also initiated a comparative microarray study of benign and malignant PHEOs, which allowed the identification of a set of about 100 genes that were differentially expressed and best discriminated the two types of tumors. A large majority of these genes were expressed at lower levels in the malignant disease and were associated with various characteristics of chromaffin cells, such as hormone secretion signaling and machinery, peptide maturation, and cellular morphology. Altogether, these studies provide novel tools for the management of PHEO, and new insights for the understanding of tumorigenesis in chromaffin cells, which may offer potential therapeutic strategies.

Phaeochromocytoma, new genes and screening strategies

Following recent advances in the genetics of phaeochromocytomas and paragangliomas, the members of the European Network for the Study of Adrenal Tumours (ENS@T) Phaeochromocytoma Working Group have decided to share their genotyping data and to propose European recommendations for phaeochromocytoma/functional paraganglioma (PH/FPGL) genetic testing. Germline DNA from 642 patients was analysed by ENS@T teams. In 166 patients (25.9%) the disease was familial and caused by germline mutations in VHL (56), SDHB (34), SDHD (31), RET (31) or NF1 (14), causing von Hippel-Lindau disease, SDHB- or SDHD-PH/FPGL syndromes, multiple endocrine neoplasia type 2 (MEN 2) and type 1 neurofibromatosis (NF1), respectively. In almost 60% of inherited cases it was possible to formulate a probable genetic diagnosis based on family history and/or typical syndromic presentation. Genetic testing revealed mutations in 12.7% of cases with an apparently sporadic presentation. Several clinical characteristics, such as young age at onset, the presence of bilateral, extra-adrenal or multiple tumours or a malignant tumour, should be seen as indications for genetic testing. The ENS@T Phaeochromocytoma Working Group recommends the genetic testing of all patients with PH and FPGL and suggests a practice algorithm for the management of their exploration.

Lack of association between microsatellite instability and benign adrenal tumors

BACKGROUND

The adrenal gland may give rise to pheochromocytomas, which are catecholamine-producing tumors originating from the adrenal medulla, or to adrenocortical tumors, which derive from the adrenocortical cortex and may be secreting or not. The genetic mechanisms underlying the formation of these tumors include somatic mutations in susceptibility genes, especially in the familial forms, and allelic loss, especially in chromosome 1.

AIM

The aim of this study was to investigate a third genetic mechanism by evaluating microsatellite instability using the reference markers (Bat25, Bat26, D2S123, D5S346, D17S250) validated by the National Cancer Institute. Microsatellite loci were analyzed in 32 benign tumors, including 11 pheochromocytomas and 21 adrenocortical tumors, in patients with and without familial syndrome.

RESULTS

The different alleles of microsatellite loci were reliably detected by DNA fragments analysis, whereas data obtained after melting-point analysis on the Lightcycler were inconsistent. No microsatellite instability was detected in any tumor. One patient with a unilateral pheochromocytoma showed a loss of heterozygosity for D17S250. A second patient with a MEN-2A syndrome and a two-sided pheochromocytoma exhibited a loss of heterozygosity for D2S123 in the right tumor only and a retention of heterozygosity for all markers in the left tumor.

CONCLUSIONS

These results suggest that microsatellite instability, evaluated by the five reference markers of the National Cancer Institute, is not a feature of benign adrenal tumors.

Mechanisms of Disease: adrenocortical tumors—molecular advances and clinical perspectives

Most adrenocortical tumors are benign, unilateral, adrenocortical adenomas that are often discovered incidentally. Adrenocortical cancer is rare. Exceptionally, adrenocortical tumors can be bilateral. Although most adrenocortical tumors occur sporadically, they may also feature in congenital and/or familial disease. The identification of germline genetic defects in familial diseases associated with adrenocortical tumors helped to define the somatic alterations in sporadic disease: for example, overexpression of insulin-like growth factor 2 and alterations at the 11p15 locus (observed in Beckwith-Wiedemann syndrome) are also found in most adrenocortical cancers. Similarly, inactivating mutations of the TP53 gene, located at 17p13 (observed in Li-Fraumeni syndrome), can also be found at the somatic level in sporadic adrenocortical cancers, as can 17p13 allelic losses. Components of the cyclic AMP signaling pathway--for example, adrenocorticotropic hormone receptors and other membrane receptors, Gs proteins and protein kinase A--can be altered to various degrees in adrenocortical tumors. More recently, gene profiling and genetic studies have shown that the Wnt-beta-catenin signaling pathway is frequently activated in adrenocortical tumors. These research findings already have profound implications for clinical management of patients with adrenocortical tumors, for example in unraveling the genetic origin of the disease in some patients, and in the development of molecular markers for diagnosis and prognosis. The new findings should also help in the development of new therapeutic options.

Functional genomics approaches for the study of sporadic adrenal tumor pathogenesis: clinical implications

Although sporadic adrenal tumors are frequently encountered in the general population their pathogenesis is not well elucidated. The advent of functional genomics/bioinformatics tools enabling large scale comprehensive genome expression profiling should contribute to significant progress in this field. Some studies have already been published describing gene expression profiles of benign and malignant adrenocortical tumors and phaeochromocytomas. Several genes coding for growth factors and their receptors, enzymes involved in steroid hormone biosynthesis, genes related to the regulation of cell cycle, cell proliferation, adhesion and intracellular metabolism have been found to be up- or downregulated in various tumors. Some alterations in gene expression appear so specific for certain tumor types that their application in diagnosis, determination of prognosis and the choice of therapy can be envisaged. In this short review, the authors will present a synopsis of these recent findings that seem to open new perspectives in adrenal tumor pathogenesis, with emphasis on changes in steroidogenic enzyme expression profiles and highlighting possible clinical implications.

Genetic basis of phaeochromocytoma and paraganglioma

Advances in the knowledge of the genetics of phaeochromocytoma have broadened our understanding about the mechanisms of tumorigenesis. Formerly it was believed that 10% of phaeochromocytomas were associated with familial cancer syndromes, but it is now recognised that up to 30% of these tumours may be familial. In particular, attention has been focused on those patients with apparently sporadic presentations where 12-24% of patients have been shown to carry germline mutations indicating hereditary disease. Consideration of genetic testing is now recommended for all apparently sporadic cases and, following the identification of a mutation-positive carrier, the offering of genetic testing to first degree relatives. There is a need for lifelong follow up of affected individuals and asymptomatic mutation-positive carriers, but validation of screening protocols has yet to be determined.

Development and validation of pheochromocytoma of the adrenal gland scaled score for predicting malignant pheochromocytomas

OBJECTIVES

To evaluate the diagnostic performances of the pheochromocytoma of the adrenal gland scaled score (PASS) proposed in a previous report and that of a logistic model developed in this investigation.

METHODS

In all 130 patients with malignant or assumed benign pheochromocytomas, 15 predictive variables were observed. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of PASS. The logistic model was developed using the 15 predictive variables. Its performance was evaluated by calculating the area under the ROC curve and comparing it with that of the PASS.

RESULTS

The PASS had the area under the ROC curve of 0.899 (95% confidence interval 0.844 to 0.954). Of the 15 variables entered in the logistic regression analysis, 9 were retained in the model. The area under the ROC curve for the logistic model was 0.983 (95% confidence interval 0.967 to 0.998).

CONCLUSIONS

ROC analysis indicated that the PASS could be used for the diagnosis of malignant pheochromocytomas. The logistic model was able to improve the diagnostic performance of the PASS using a different variable weighting method. We emphasize, however, that a clinical prospective evaluation is needed to confirm their actual value.

New Advances in the Genetics of Pheochromocytoma and Paraganglioma Syndromes

The discovery of the SDH genes in 2000/2001 dramatically changed the genetics of pheochromocytoma (PHEO) and paraganglioma (PGL). Five years on, it is widely accepted that all patients with PHEO/PGL, whatever their age, should undergo genetic testing, because 25-30% of PHEOs are caused by a germline mutation in one of the five PHEO susceptibility genes. However, genetic testing should be targeted according to family and clinical history. The identification of a causal mutation modifies the management and follow-up of the patient and provides an opportunity for presymptomatic genetic testing for other family members. Moreover, the demonstration that the SDH genes, are tumor suppressor genes and that their inactivation is involved in the hypoxia-angiogenic pathway activating the transcription factor hypoxia-inducible factor (HIF) by inhibiting prolyl hydroxylases (PHDs) may lead to the identification of new therapeutic targets for these rare diseases. We discuss here these recent findings and their clinical consequences for the management of PHEO/PGL families and the future of research in this field.

Genetic Testing in Pheochromocytoma: Increasing Importance for Clinical Decision Making

Hereditary pheochromocytomas and paragangliomas are caused by germline mutations in syndrome-associated genes. This includes multiple endocrine neoplasia Type 2 (MEN 2) caused by mutations in the RET proto-oncogene, von Hippel-Lindau (VHL) syndrome due to mutations of the VHL gene, neurofibromatosis Type I (NF1) caused by mutations of the NF1 gene, and pheochromocytoma/paraganglioma syndromes due to mutations in genes encoding the succinate dehydrogenase subunits D (SDHD) and B (SDHB). At the First International Symposium on Pheochromocytoma (ISP2005) organized by the National Institutes of Health, a panel of specialist clinicians and scientists from around the world addressed the topic of genetic testing in pheochromocytoma patients. This review summarizes the discussions and conclusions of the panel and provides a recommendation for evidence-based management of genetic testing in these patients and their families. A pragmatic algorithm is presented, taking into account patient age, tumor location (extra-adrenal, intra-adrenal, unilateral, and bilateral), biochemical presentation, and financial costs. This was based on cumulative frequencies ranging from 7.5% to 29% for germline mutations in four genes (RET, VHL, SDHB, and SDHD) in patients with apparently sporadic pheochromocytomas. This algorithm will need to be validated by further genetic analysis, multicenter studies, and long-term observations.

Transcatheter arterial embolization for the treatment of liver metastases in a patient with malignant pheochromocytoma

A 63-year-old male patient was admitted for the treatment of malignant pheochromocytoma with multiple liver metastases. Plasma and urinary levels of catecholamines were elevated. Transcatheter arterial embolization (TAE) with concomitant administration of mitomycin C and gelatin sponge was performed for the treatment of liver metastases. Dose of alpha-1 blocker before TAE was increased to prevent hypertensive crisis during and after TAE. The hepatic metastatic lesion of CT findings was decreased after TAE. Although blood pressure showed a transient hypertension (180/100 mmHg) after every TAE, it returned rapidly to normal. The patient experienced transient abdominal pain, nausea, and loss of appetite after every TAE; however, those symptoms were readily controlled by conventional medications. Slight elevation of liver transaminases was recognized but returned to normal range within 3 weeks. No other major side effects were seen with TAE. While plasma and urinary level of catecholamines were unchanged, plasma chromogranin A (CgA) level was significantly decreased. These results suggest that TAE is a useful treatment for hepatic metastases. Plasma CgA level is a useful marker in the treatment of malignant pheochromocytoma.

Histopathology and immunohistochemistry of adrenal medullary tumors and paragangliomas

Paragangliomas arise from sympathetic or parasympathetic paraganglia and should now be defined by their site and type. The term pheochromocytoma is reserved for intra-adrenal tumors. This short review discusses the gross and microscopic features, the immunohistochemical profile, the problem of recognizing malignant potential, and the rare instances where a differential diagnosis has to be considered.

PRKAR1A mutations in primary pigmented nodular adrenocortical disease

Primary Pigmented Nodular Adrenocortical Disease (PPNAD) is a rare primary bilateral adrenal defect causing corticotropin-independent Cushing's syndrome. It occurs mainly in children and young adults. Macroscopic appearance of the adrenals is characteristic with small pigmented micronodules observed in the cortex. PPNAD is most often diagnosed in patients with Carney complex (CNC), but it can also be observed in patients without other manifestations or familial history (isolated PPNAD). The CNC is an autosomal dominant multiple neoplasia syndrome characterized by the association of myxoma, spotty skin pigmentation and endocrine overactivity. One of the putative CNC genes has been identified as the gene of the regulatory R1A subunit of protein kinase A (PRKAR1A), located at 17q22-24. Germline heterozygous inactivating mutations of PRKAR1A have been reported in about 45% of patients with CNC, and up to 80% of CNC patients with Cushing's syndrome due to PPNAD. Interestingly, such inactivating germline PRKAR1A mutations have also been found in patients with isolated PPNAD. The hot spot PRKAR1A mutation termed c.709[-7-2]del6 predisposes mostly to isolated PPNAD, and is the first clear genotype/phenotype correlation described for this gene. Somatic inactivating mutations of PRKAR1A have been observed in macronodules of PPNAD and in sporadic cortisol secreting adrenal adenomas. Isolated PPNAD is a genetic heterogenous disease, and recently inactivating mutations of the gene of the phosphodiesterase 11A4 (PDE11A4) located at 2q31-2q35 have been identified in patients without PRKAR1A mutations. Interestingly, both PRKAR1A and PDE11A gene products control the cAMP signaling pathway, which can be altered at various levels in endocrine tumors.