Paraganglioma-like dermal melanocytic tumor: a case report with particular features

Childhood dermal tumors with melanocytic features is an unusual tumor that can create diagnostic confusion. Among them, paraganglioma-like melanocytic tumors- previous included in melanocytic tumors of uncertain malignant potential- has some particular histopathologic and immunohistochemical features. We describe a case of 13 years old girl with a paraganglioma-like dermal melanocytic tumor of the left leg.

6-[F-18]Fluoro-L-dihydroxyphenylalanine positron emission tomography is superior to conventional imaging with (123)I-metaiodobenzylguanidine scintigraphy, computer tomography, and magnetic resonance imaging in localizing tumors causing catecholamine excess

CONTEXT

Catecholamine excess is rare, but symptoms may be life threatening.

OBJECTIVE

The objective of the study was to investigate the sensitivity of 6-[F-18]fluoro-l-dihydroxyphenylalanine positron emission tomography ((18)F-DOPA PET), compared with (123)I-metaiodobenzylguanidine ((123)I-MIBG) scintigraphy and computer tomography (CT)/magnetic resonance imaging (MRI) for tumor localization in patients with catecholamine excess.

DESIGN AND SETTING

All consecutive patients with catecholamine excess visiting the University Medical Center Groningen, Groningen, The Netherlands, between March 2003 and January 2008 were eligible.

PATIENTS

Forty-eight patients were included. The final diagnosis was pheochromocytoma in 40, adrenal hyperplasia in two, paraganglioma in two, ganglioneuroma in one, and unknown in three.

MAIN OUTCOME MEASURES

Sensitivities and discordancy between (18)F-DOPA PET, (123)I-MIBG, and CT or MRI were analyzed for individual patients and lesions. Metanephrines and 3-methoxytyramine in plasma and urine and uptake of (18)F-DOPA with PET were measured to determine the whole-body metabolic burden and correlated with biochemical tumor activity. The gold standard was a composite reference standard.

RESULTS

(18)F-DOPA PET showed lesions in 43 patients, (123)I-MIBG in 31, and CT/MRI in 32. Patient-based sensitivity for (18)F-DOPA PET, (123)I-MIBG, and CT/MRI was 90, 65, and 67% (P < 0.01 for (18)F-DOPA PET vs. both (123)I-MIBG and CT/MRI, P = 1.0 (123)I-MIBG vs. CT/MRI). Lesion-based sensitivities were 73, 48, and 44% (P < 0.001 for (18)F-DOPA PET vs. both (123)I-MIBG and CT/MRI, P = 0.51 (123)I-MIBG vs. CT/MRI). The combination of (18)F-DOPA PET with CT/MRI was superior to (123)I-MIBG with CT/MRI (93 vs. 76%, P < 0.001). Whole-body metabolic burden measured with (18)F-DOPA PET correlated with plasma normetanephrine (r = 0.82), urinary normetanephrine (r = 0.84), and metanephrine (r = 0.57).

CONCLUSION

To localize tumors causing catecholamine excess, (18)F-DOPA PET is superior to (123)I-MIBG scintigraphy and CT/MRI.

Malignant pheochromocytomas and paragangliomas: molecular signaling pathways and emerging therapies

Patients having malignant pheochromocytomas and paragangliomas traditionally have been treated with systemic chemotherapy and (131)I-meta-iodobenzylguanidine. However, these therapies have limited efficacy and the potential for significant toxicity. Over the last decade, researchers have discovered new gene mutations associated with malignant pheochromocytomas and paragangliomas, facilitating a better understanding of the molecular pathways involved in the development of these tumors. This new knowledge has brought with it the potential to test new medications that specifically target the signal transduction abnormalities known to be involved in malignant transformation. We are among the groups to have recently reported the use of the tyrosine kinase inhibitor sunitinib in a limited number of patients with malignant pheochromocytomas and paragangliomas. The use of sunitinib was associated with a reduction in the size of the tumors, their biochemical markers, and symptomatic improvement. In this review, we will explore these newly understood molecular pathways and the emerging therapies that may change the management of this disease.

[Diagnosis and evaluation of head and neck paragangliomas. Clinical and biological manifestations]

Head and neck paragangliomas are slow-growing tumors and the initial symptoms are sometimes non-specific, often hampering and delaying diagnosis. These tumors may be asymptomatic, even when they have reached a considerable size. Symptomatology is highly varied in terms of anatomical location, stage (degree of invasion, local involvement and the presence of metastasis) and catecholamine secretion (pheochromocytoma), which not only produces a series of systemic manifestations but also serves as a guide to the search for specific genetic diseases, of which these tumors may be a component. Thus, in addition to identifying their anatomical location, excess catecholamine production must be assessed and genetic diagnosis must be completed before surgery is performed.

Somatostatin-producing neuroendocrine tumors of the duodenum and pancreas: incidence, types, biological behavior, association with inherited syndromes, and functional activity

Somatostatin-producing neuroendocrine tumors (SOM-NETs) of the duodenum and pancreas appear to be heterogeneous. To determine their clinicopathological profiles, respective data were analyzed on a series of 82 duodenal and 541 pancreatic NETs. In addition, the clinical records of 821 patients with duodenal or pancreatic NETs were reviewed for evidence of a somatostatinoma syndrome. Predominant or exclusive expression of somatostatin was found in 21 (26%) duodenal and 21 (4%) pancreatic NETs. They were classified as sporadic (n=31) or neurofibromatosis type 1 (NF1)-associated duodenal NETs (n=3), gangliocytic paragangliomas (GCPGs; n=6), or poorly differentiated neuroendocrine carcinomas (pdNECs; n=2). In addition, five duodenal and four pancreatic SOM-NETs were found in five patients with multiple endocrine neoplasia type 1 (MEN1). Metastases occurred in 13 (43%) patients with sporadic or NF1-associated SOM-NETs, but in none of the duodenal or pancreatic MEN1-associated SOM-NETs or GCPGs. Sporadic advanced (stage IV) SOM-NETs were more commonly detected in the pancreas than in the duodenum. None of the patients (including the 821 patients for whom only the clinical records were reviewed) fulfilled the criteria of a somatostatinoma syndrome. Our data show that somatostatin expression is not only seen in sporadic NETs but may also occur in GCPGs, pdNECs, and hereditary NETs. Surgical treatment is effective in most duodenal and many pancreatic SOM-NETs. MEN1-associated SOM-NETs and GCPGs follow a benign course, while somatostatin-producing pdNECs are aggressive neoplasms. The occurrence of the so-called somatostatinoma syndrome appears to be extremely uncommon.

A retroperitoneal sympathetic paraganglioma invading the duodenum and mimicking a submucosal tumor

We report a case of an autopsy of unusual retroperitoneal sympathetic paraganglioma (SPG) that directly invaded the duodenum and showed expansive growth mimicking a submucosal tumor. The tumor was clinically suspected to be a gastrointestinal stromal tumor (GIST) of the duodenum because of its location and extension to the retroperitoneum without catecholamine-associated symptoms. However, a small biopsy specimen of the tumor showed diffuse proliferation of large basophilic cells that were negative for C-kit and CD34, ruling out GIST and indicating an epithelial malignancy. An autopsy revealed that the tumor was mainly in the retroperitoneum, measuring 7.5 x 9.5 cm, weighing 600 g and extending into the duodenum, adjacent to the pancreas but free of the adrenal glands. On cut section, the tumor involved the entire wall of the duodenum. There were no metastases in any organs. For differential diagnosis, endocrine tumors of the duodenum or pancreas and extra-adrenal SPG were considered. The tumor cells were immunohistochemically strongly positive for chromogranin A and were surrounded by cells positive for S100 protein. The Ki67-labeling index was under 1%. The four catecholamine-synthesizing enzymes were detected in the tumor cells. We report this case of SPG with emphasis on differential diagnosis and the significance of its local invasion.

Stathmin expression in pheochromocytomas, paragangliomas, and in other endocrine tumors

Pheochromocytomas are neuroendocrine tumors confined to the adrenal glands, and malignant pheochromocytomas can spread to various sites including the liver, lung, and bones. Paragangliomas occur in numerous locations in the body, so assessment of metastatic disease is more challenging, as patients with familial syndromes often have multiple, possibly independent paragangliomas. The most reliable criterion for malignancy in pheochromocytomas and paragangliomas is metastatic disease. Because there are few immunohistochemical markers that are useful in the diagnosis of malignancy in pheochromocytomas and paragangliomas before they metastasize, more markers are needed to characterize these tumors. Stathmin is a widely expressed 17-kDa cytoplasmic, microtubule destabilizing and sequestering phosphoprotein that is important in cell motility and cancer cell metastasis. It is upregulated in various malignancies. We examined stathmin expression in tissues from patients with pheochromocytomas (n = 48), malignant pheochromocytomas (n = 28), paragangliomas (n = 42), and malignant paragangliomas (n = 21) by immunohistochemistry using tissue microarrays (TMA) with a polyclonal antibody against stathmin. A series of other endocrine tissues and tumors (n = 70) were also examined for stathmin expression. Stathmin was more highly expressed in pheochromocytomas compared to normal adrenals, a finding confirmed by Western blot. There was higher expression of stathmin by immunohistochemical staining in malignant pheochromocytomas compared to pheochromocytomas without metastasis when analyzed by maximal staining (p = 0.012). Stathmin was present in a wide variety of endocrine tumors and was most highly expressed in rapidly proliferating tumors including anaplastic thyroid carcinomas, Merkel cell carcinomas of the skin and small cell carcinomas of the lung. These results show that stathmin is expressed at higher levels in more rapidly proliferating endocrine tumors. However, it is probably not useful as a stand-alone marker to determine malignancy in pheochromocytomas for individual tumors.

Increased HIF1 alpha in SDH and FH deficient tumors does not cause microsatellite instability

Germline mutations in nuclear genes encoding mitochondrial enzymes fumarate hydratase (FH) and succinate dehydrogenase (subunits SDHB/C/D) have been implicated in the development of tumor syndromes referred to as hereditary leiomyomatosis and renal cell cancer (HLRCC) and hereditary paragangliomatosis (HPGL), respectively. FH and SDH are operating in the tricarboxylic acid cycle (the TCA cycle, the Krebs cycle). In the FH and SDH deficient tumors, accumulation of the substrates, fumarate and succinate, has been shown to cause stabilization of hypoxia inducible factor 1 alpha (HIF1 alpha). According to recent studies, HIF1 alpha could contribute to the hypoxia induced genomic instability seen in many cancers, through repression of mismatch repair (MMR) protein MSH2. In this study, in agreement with previous works, we found HIF1 alpha to be moderately or highly stabilized in 67% (16/24) and 77% (48/62) of HLRCC tumors and SDHB/C/D paragangliomas (PGL) and pheochromocytomas (PHEO), respectively. In addition, a set of 54 other familial and nonfamilial PGLs/PHEOs were studied. Moderately or highly stabilized HIF1 alpha was present in 68% (26/38) of the PGLs but in PHEOs (n = 16) no such pattern was observed. We then analyzed the suggested link between HIF1 alpha stabilization and MSH2 repression, in HLRCC and HPGL tumor material. No microsatellite instability (MSI) or lack of MSH2 expression was, however, observed. Thus we failed to provide in vivo evidence for the proposed link between HIF1 alpha stabilization and functional MMR deficiency, in TCAC deficient tumors.

Gangliocytic paraganglioma: case report and review of the literature

Gangliocytic paraganglioma is a rare tumor, which occurs nearly exclusively in the second portion of the duodenum. Generally, this tumor has a benign clinical course, although rarely, it may recur or metastasize to regional lymph nodes. Only one case with distant metastasis has been reported. We present a case of duodenal gangliocytic paraganglioma treated first by local resection followed by pylorus-preserving pancreaticoduodenectomy. Examination of the first specimen revealed focal nuclear pleomorphism and mitotic activity, in addition to the presence of three characteristic histologic components: epithelioid, ganglion, and spindle cell. In the subsequent pancreaticoduodenectomy specimen, there was no residual tumor identified in the periampullary area, but metastatic gangliocytic paraganglioma was present in two of seven lymph nodes. This case report confirms the malignant potential of this tumor. We review the published literature on gangliocytic paragangliomas pursuing a malignant course. We conclude that surgical therapy of these neoplasms should not be limited to local resection, as disease recurrence, lymph node involvement, and rarely distant metastasis may occur.

Peptide products of the neurotrophin-inducible gene vgf are produced in human neuroendocrine cells from early development and increase in hyperplasia and neoplasia

BACKGROUND

Although the neurotrophin-inducible gene vgf is expressed in mammalian neurons and endocrine cells, limited data is available in man.

AIM

The objective of the study was to map proVGF peptides in human endocrine cells during development, adulthood, hyperplasia, and tumors.

METHODS

Antisera were generated against peptides related to internal cleavage or cleavage-amidation sites (rat proVGF(422-430) and human proVGF(298-306)-NH2) and the proVGF C-terminal ending (human proVGF(607-615)). Developing and normal adult endocrine cells, hyperplastic endocrine lesions (thyroid, parathyroid, lung, and stomach), and 120 tumors (102 endocrine) were studied. Immunogold electron microscopy was performed on normal adult pancreas and gut, and Western blotting was performed on extracts of control tissues and endocrine tumors.

RESULTS

proVGF fragments were revealed in developing pituitary, gut, pancreas, and adrenal medulla from 10 gestational weeks, in normal adult pituitary and adrenal medulla, pancreatic glucagon, and insulin cells and gut serotonin cells, in hyperplastic thyroid calcitonin cells, lung P cells, gastric enterochromaffin-like cells, and gastrin cells, and in 88 of 102 endocrine tumors. At electron microscopy proVGF immunoreactivity was restricted to electron-dense granules. Western blotting revealed large molecular weight forms and cleavage fragments in both control tissues and tumor extracts.

CONCLUSIONS

proVGF-related peptides are present in endocrine cells early during development and adulthood and increase in hyperplasia and tumors, and proVGF fragments could be novel diagnostic tools for endocrine cells and related lesions, including tumors.

Pheochromocytoma: recommendations for clinical practice from the First International Symposium. October 2005

The First International Symposium on Pheochromocytoma, held in October 2005, included discussions about developments concerning these rare catecholamine-producing tumors. Recommendations were made during the symposium for biochemical diagnosis, localization, genetics, and treatment. Measurement of plasma or urinary fractionated metanephrines, the most accurate screening approach, was recommended as the first-line test for diagnosis; reference intervals should favor sensitivity over specificity. Localization studies should only follow reasonable clinical evidence of a tumor. Preoperative pharmacologic blockade of circulatory responses to catecholamines is mandatory. Because approximately a quarter of tumors develop secondary to germ-line mutations in any one of five genes, mutation testing should be considered; however, it is not currently cost effective to test every gene in every patient. Consideration of tumor location, presence of multiple tumors, presence of metastases, and type of catecholamine produced is useful in deciding which genes to test. Inadequate methods to distinguish malignant from benign tumors and a lack of effective treatments for malignancy are important problems requiring further resolution.

Hypoglycemia due to ectopic release of insulin from a paraganglioma

Insulin-secreting pancreatic tumors and insulin-like growth hormone-secreting non-islet cell tumors can cause hypoglycemia. However, insulin-releasing paraganglioma or pheochromocytoma has almost never been reported. A 67-year-old female patient was admitted to our hospital because of headache, palpitation, perspiration, faintness, frequent sense of hunger and absent-mindedness. These intermittent symptoms had begun approximately a year before admission. On physical examination, she had high blood pressure of 150/90 mm Hg. Hormonal studies demonstrated increased urinary norepinephrine levels, and hyperinsulinemic hypoglycemia was confirmed while the patient was symptomatic. Abdominal MRI revealed a retroperitoneal mass measuring 4.5 cm in the pancreatic region. She was treated with an alpha-blocking agent to control blood pressure preceding the removal of the mass. Histopathological diagnosis was paraganglioma, and immunohistochemically insulin staining in the neoplastic cells was demonstrated. Her blood pressure normalized and hypoglycemia relieved after the operation. The patient did not have recurrence of hypoglycemia after a year of follow-up. Paraganglioma is a rare tumor of the neural crest, and co-secretion of insulin and catecholamines has been reported only by a single case report in the literature. The present patient is another case with this co-secretion.

A case of catecholamine and glucocorticoid excess syndrome due to a corticotropin-secreting paraganglioma

We present a case of a 61-year-old female patient with ectopic corticotropin (ACTH) syndrome, hypopituitarism, and catecholamine excess due to a paraganglioma at the inferior pole of the left kidney. In this article we discuss the hormonal findings in the patient and its consequences, the pitfalls of the endocrine workup, and the results of our immunohistological and molecular studies in more detail.

Expression of HIF-1alpha, HIF-2alpha (EPAS1), and their target genes in paraganglioma and pheochromocytoma with VHL and SDH mutations

CONTEXT

Activation of the hypoxia-inducible transcription factors HIF-1 and HIF-2 and a HIF-independent defect in developmental apoptosis have been implicated in the pathogenesis of pheochromocytoma (PCC) associated with VHL, SDHB, and SDHD mutations.

OBJECTIVE

Our objective was to compare protein (HIF-1alpha, EPAS1, SDHB, JunB, CCND1, CD34, CLU) and gene (VEGF, BNIP3) expression patterns in VHL and SDHB/D associated tumors.

RESULTS

Overexpression of HIF-2 was relatively more common in VHL than SDHB/D PCC (12 of 13 vs. 14 of 20, P = 0.02), whereas nuclear HIF-1 staining was relatively more frequent in SDHB/D PCC (19 of 20 vs. 13 of 16, P = 0.04). In addition, CCND1 and VEGF expression (HIF-2 target genes) was significantly higher in VHL than in SDHB/D PCC. These findings suggest that VHL inactivation leads to preferential HIF-2 activation and CCND1 expression as described previously in VHL-defective renal cell carcinoma cell lines but not in other cell types. These similarities between the downstream consequences of VHL inactivation and HIF dysregulation in renal cell carcinoma and PCC may explain how inactivation of the ubiquitously expressed VHL protein results in susceptibility to specific tumor types. Both VHL and SDHB/D PCC demonstrated reduced CLU and SDHB expression. SDHB PCC are associated with a high risk of malignancy, and expression of (proapototic) BNIP3 was significantly lower in SDHB than VHL PCC.

CONCLUSION

Although inactivation of VHL and SDHB/D may disrupt similar HIF-dependent and HIF-independent signaling pathways, their effects on target gene expression are not identical, and this may explain the observed clinical differences in PCC and associated tumors seen with germline VHL and SDHB/D mutations.

High frequency of SDHB germline mutations in patients with malignant catecholamine-producing paragangliomas: implications for genetic testing

CONTEXT

Adrenal and extraadrenal paragangliomas are tumors of chromaffin cells that are usually benign but that may also develop into malignant disease. Mutations of the gene for succinate dehydrogenase subunit B (SDHB) are associated with a high risk of malignancy, but establishing the precise contribution requires relatively large numbers of patients with well-defined malignancy.

OBJECTIVE

We assessed the prevalence of SDHB mutations in a series of patients with malignant paraganglioma.

DESIGN

SDHB mutation testing was carried out in 44 consecutive patients with malignant paraganglioma. Clinical characteristics of patients with malignant disease due to SDHB mutations were compared with those without mutations.

RESULTS

Pathogenic SDHB mutations were found in 13 of the 44 patients (30%). Close to one third of patients had metastases originating from an adrenal primary tumor, compared with a little over two thirds from an extraadrenal tumor. Among the latter patients, the frequency of SDHB mutations was 48%.

CONCLUSION

This study establishes that missense, nonsense, frameshift, and splice site mutations of the SDHB gene are associated with about half of all malignancies originating from extraadrenal paragangliomas. The high frequency of SDHB germline mutations among patients with malignant disease, particularly when originating from an extraadrenal paraganglioma, may justify a high priority for SDHB germline mutation testing in these patients.

Suprasellar and intrasellar paragangliomas

Neoplasms of the sellar region are entities with a large differential diagnosis. Although paraganglionic cells have not been demonstrated in the pituitary or adjacent structures, the existence of sellar region paragangliomas is well-documented. To elucidate, in this area the nature of these unusual tumors is relatively difficult. Clinical history, physical examination, radiographic investigation as well as intraoperative gross observation are the same as those of sellar meningioma or pituitary adenoma. Immunohistochemistry, using neuroendocrine markers and electron microscopy are the two definitive diagnostic methods to differentiate among these entities. The clinical management, the possible pathogenesis of the tumor, the importance of immunohistochemistry in making the diagnosis and the clinical outcome of these patients are discussed.

Basic fibroblast growth factor and fibroblastic growth factor receptor-1 may contribute to head and neck paraganglioma development by an autocrine or paracrine mechanism

Paragangliomas are hypervascular tumors arising from neural crest-derived paraganglia that are associated with the autonomic nerve system. Mutations in genes coding for subunits of mitochondrial complex II are associated with hereditary paragangliomas, and it has been suggested that these mutations result in a pseudohypoxic signal triggering tumorigenesis. Fibroblastic growth factors are hypoxia-inducible angiogenic stimuli that are involved in the angiogenesis and tumorigenesis of several neoplasms. It has been demonstrated that basic fibroblastic growth factor (bFGF) is a survival factor for cultured chief cells of the carotid body, capable of inducing proliferation. To examine the role of this growth factor in paragangliomas, we studied the immunohistochemical expression of bFGF and its high affinity receptor fibroblastic growth factor receptor 1 (FGFR1) in 7 normal carotid bodies and in 33 head and neck paragangliomas, including 2 malignant cases and their metastases. Immunohistochemical expression of bFGF and FGFR1 in tumors was confirmed by real-time polymerase chain reaction. FGFR1 was moderately present in carotid bodies, and there was strong and significantly enhanced cytoplasmatic staining of FGFR1 in all paragangliomas. Chief cells in carotid bodies and tumors showed strong cytoplasmatic staining for bFGF. The results indicate that FGFR1 and bFGF may contribute to the development of head and neck paragangliomas.

Primary cutaneous paraganglioma of the scalp

Paragangliomas are neuroendocrine tumors that arise in relation to the sympathetic or parasympathetic ganglia of the autonomic nervous system. Rarely, they are reported in unusual locations such as the urinary bladder, prostate, and uterus. Herein, we report a case of primary cutaneous paraganglioma of the scalp in a child. The tumor was studied histologically, immunohistochemically, and ultrastructurally. This case might represent an aberrant migration of neural crest cells in their descent toward the branchial arches. In addition, it highlights the complex interaction of the neural crest and branchial arches/clefts during embryogenesis.

Epidermal growth factor receptor expression and activation in neuroendocrine tumours

Epidermal growth factor receptor (EGFR) is expressed in many cancers and is associated with poor prognosis. EGFR activation pathways have been well characterised using tumour cell lines and are known to involve EGFR activation through autophosphorylation. Phosphorylation of downstream signalling molecules, such as ERK1/2 (extra-cellular regulated kinase 1 and 2) and PKB/Akt (protein kinase B), leads to enhanced tumour cell survival and proliferation. Although EGFR expression has been determined in neuroendocrine tumour tissue, its activation and subsequent effects on the downstream signalling molecules, ERK1/2 and Akt, have not been studied. We therefore planned to determine the role of EGFR in neuroendocrine tumours (NETs) by determining its pattern of expression and activation, and the subsequent activation of downstream signalling molecules ERK1/2 and Akt. Paraffin-embedded tumour tissue was available from 98 patients with NETs (39 foregut, 42 midgut, four hindgut, five paragangliomas, and four of unknown origin). Immunohistochemical evaluation was performed for the expression of EGFR, p-EGFR, p-Akt, and p-ERK1/2. Ninety-six percent of tumour samples were positive for EGFR expression; 63% were positive for activated EGFR; 76% were positive for activated Akt; and 96% were positive for activated ERK1/2. Importantly, the histological score for the activation of Akt and ERK1/2 correlated with the histological score for activated EGFR. These data provide a rationale for considering EGFR inhibitors in the treatment of NETs. Additionally, direct inhibition of Akt and ERK1/2 may provide further therapeutic options in the treatment of NETs in the future.