Paraganglioma as a systemic syndrome: pitfalls and strategies

Surgical outcomes for carotid body tumour resection without preoperative embolization: a 10-year experience

Background

Carotid body tumours (CBTs) are neoplasms originating from the paraganglionic cells of the carotid body. Excision is the main route of treatment. This study sought to assess the surgical outcomes of post-carotid body tumour resection without preoperative embolization and discern any underlying relationships between modified Shamblin classes (MSC) and related complications.

Methods

A retrospective medical record review of prospectively collected data is performed at Sulaymaniyah Teaching Hospital between 2008 and 2019, for 54 patients. Presurgical and postsurgical variables such as comorbidities and complications were noted, respectively.

Results

Patient ages ranged between 26 and 60 years (x̄=40.06) with a minimal female predominance (57.4%). Complications included one minor stroke. MSC and postoperative complications were significantly related (P≤0.001). Our analyses also suggested a significant relationship between intraoperative blood loss and the incidence of postoperative complications (P=0.001, χ²=25). The MSC III subtype was significantly associated with intraoperative blood loss (P=0.000), length of stay (P=0.000), and operating time (P=0.001).

Conclusions

Our study purports a strong relationship between greater MSC and complications of all types. As such, surgeons may benefit from preoperative strategies to minimize complications.

Thyroid Paraganglioma With Medullary Carcinoma: A Unique Combination in a Patient in Association With Multiple Endocrine Neoplasia Type 2B Syndrome With Prolonged Survival

Head and neck paragangliomas (PGLs) most commonly derive from the carotid body, jugulotympanic, vagal, and laryngeal paraganglia. Thyroid PGLs originate in the inferior laryngeal paraganglion, which may lie inside the thyroid parenchyma. Intrathyroid PGLs are rare with approximately 75 cases reported to date, mostly as solitary lesions. The coexistence of thyroid PGL with medullary thyroid carcinoma (MTC) has not been reported. Here, we report a unique case of intrathyroid PGL concomitant with MTC in the context of multiple endocrine neoplasia type 2B syndrome. Interestingly, the patient showed a prolonged survival with good clinical response to tyrosine kinase inhibitors, despite her advanced metastatic MTC. We discuss the challenges in pathology, differential diagnosis, and genetic background for the development of these thyroid lesions.

Multiple endocrine neoplasia type 2: A reveiw

Multiple endocrine neoplasias are rare hereditary syndromes some of them with malignant potential. Multiple endocrine neoplasia type 2 (MEN 2) is an autosomal dominant hereditary cancer syndrome due to germline variants in the REarranged during Transfection (RET) proto-oncogene. There are two distinct clinical entities: MEN 2A and MEN 2B. MEN 2A is associated with medullary thyroid carcinoma (MTC), phaeochromocytoma, primary hyperparathyroidism, cutaneous lichen amyloidosis and Hirschprung's disease and MEN 2B with MTC, phaeochromocytoma, ganglioneuromatosis of the aerodigestive tract, musculoskeletal and ophthalmologic abnormalities. Germline RET variants causing MEN 2 result in gain-of-function; since the discovery of the genetic variants a thorough search for genotype-phenotype associations began in order to understand the high variability both between families and within family members. These studies have successfully led to improved risk classification of prognosis in relation to the genotype, thus improving the management of the patients by thorough genetic counseling. The present review summarizes the recent developments in the knowledge of these hereditary syndromes as well as the impact on clinical management, including genetic counseling, of both individual patients and families. It furthermore points to future directions of research for better clarification of timing of treatments of the various manifestations of the syndromes in order to improve survival and morbidity in these patients.

Carotid Body Tumor Microenvironment

Carotid body tumors (CBTs) are rare paragangliomas, comprising 0.5% of all head and neck tumors, and 65% of head and neck paragangliomas. A majority of CBTs occur sporadically, while 15% are familial or hyperplastic in the setting of chronic hypoxia. They usually present as unilateral, well-circumscribed rubbery masses, arising at the level of the carotid bifurcation. A majority of CBTs are painless and therefore may evade diagnosis for months to years. Symptomatic lesions occur due to progressive cranial nerve IX, X, or XII dysfunction, manifesting as hoarseness, dysphagia, vertigo, coughing, or odynophagia. Other local symptoms include neck discomfort, pulsatile tinnitus, hearing loss, or carotid sinus syndrome. Appropriate workup includes a thorough physical exam followed by radiographic imaging, vascular studies, and biochemical workup with 24 h urinary catecholamine or metanephrine analysis. The management of these tumors, which involves standalone surgical resection or following embolization for larger and more vascular tumors, will also be discussed.

Surgical Versus Sequential Hybrid Treatment of Carotid Body Tumors

Carotid body tumor (CBT) are slow-growing tumors that develop in the cervical region at the carotid bifurcation. . In a randomized study, 33 patients were treated for CBT excision: 10 patients performed preoperative embolization (PE) and 23 were treated only by isolated traditional surgery (N-PE). The first group includes patients undergoing preoperative embolization. The second group of patients (N-PE) included 11 males and 12 females. Intraoperative complications were lower in patients treated with a hybrid procedure (PE): sections of the cranial nerves were recorded in 7% of cases compared to 12% of the surgical procedure (P-value = 0.72); while the reversible nerve lesions (P value = 0.21) and the permanent ones (P value = 0.46), were instead similar in both procedures. The comparative blood loss during the operative procedure shows a P-value of 0.02. Operating times, reversible damage of the cranial nerves , incidence of stroke (0% vs1%, P value> 0.99) and post-operative hospital stay (4.1 vs. 4.2 days, P value = 0.91) did not show differences in the two groups of patients. The analysis of the results detects pre-operative embolization of CBT in reducing intraoperative blood loss and resection of the cranial nerves..

Oxygen sensing and stem cell activation in the hypoxic carotid body

The carotid body (CB) is the major arterial chemoreceptor responsible for the detection of acute decreases in O₂ tension (hypoxia) in arterial blood that trigger hyperventilation and sympathetic activation. The CB contains O₂-sensitive glomus (chief) cells, which respond to hypoxia with the release of transmitters to activate sensory nerve fibers impinging upon the brain respiratory and autonomic centers. During exposure to sustained hypoxia (for weeks or months), the CB grows several-fold in size, a response associated with acclimatization to high altitude or to medical conditions presenting hypoxemia. Here, I briefly present recent advances on the mechanisms underlying glomus cell sensitivity to hypoxia, in particular the role of mitochondrial complex I in acute oxygen sensing. I also summarize the properties of adult CB stem cells and of glomus cell-stem cell synapses, which contribute to CB hypertrophy in chronic hypoxia. A note on the relationship between hypoxic CB growth and tumorigenesis is included. Finally, the medical implications of CB pathophysiology are discussed.

PRECISION MEDICINE: AN UPDATE ON GENOTYPE/BIOCHEMICAL PHENOTYPE RELATIONSHIPS IN PHEOCHROMOCYTOMA/PARAGANGLIOMA PATIENTS

OBJECTIVE

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors known to produce and secrete high levels of circulating catecholamines and their metabolites. The biochemical characteristics of these tumors can be used to divide them into three major phenotypes. The adrenergic, noradrenergic and dopaminergic phenotypes are defined by predominant elevations in epinephrine and metanephrine, norepinephrine and normetanephrine, and dopamine and 3-methoxytyramine, respectively. There are over 15 well-identified tumor-susceptibility genes responsible for approximately 40% of the cases. The objective of this review article is to outline specific genotype/biochemical phenotype relationships.

METHODS

Literature review.

RESULTS

None.

CONCLUSION

Biochemical phenotype of PPGL is determined by the underlying genetic mutation and the associated molecular pathway. Identification of genotype/biochemical relationships is valuable in prioritizing testing for specific genes, making treatment decisions and monitoring disease progression.

ABBREVIATIONS

3-MT = 3-methoxytyramine; EPAS1 = endothelial pas domain protein 1; FH = fumarate hydratase; HIF2A = hypoxia inducible factor type 2A; MEN2 = multiple endocrine neoplasia type 2; NF1 = neurofibromatosis type 1; PNMT = phenylethanolamine N-methyltransferase; PPGL = pheochromocytoma and paraganglioma; RET = rearranged during transfection; SDH = succinate dehydrogenase; SDHAF2 = succinate dehydrogenase complex assembly factor 2; TCA = tricarboxylic acid; TH = tyrosine hydroxylase; TMEM127 = transmembrane protein 127; VHL = von Hippel-Lindau.

Treatment of glomus tympanicum tumors by preoperative embolization and total surgical resection

PURPOSE

The purpose of this study was to evaluate the effectiveness on function preservation and tumor control of the treatment of glomus tympanicum tumors with pre-operative embolization followed by total surgical resection.

MATERIAL AND METHODS

We describe a series of 6 patients with a glomus tympanicum tumor who were treated in our hospital using the same technique: the day before surgery selective tumor embolization due to denaturation with 96% ethanol. Following parameters were considered: tumor classification, tumor control, clinical and audiological outcome, effectiveness of embolization, percentage of tumor necrosis and treatment complications.

RESULTS

There were no severe complications due to embolization or surgery. Tumor blush disappeared completely in 5 patients on DSA post embolization and histologic evaluation of the resected tissue showed a median of 69.2% of tumor necrosis. Pulsatile tinnitus disappeared in all patients and 3 patients had no symptoms at all. Hearing ameliorated in 4 patients, 1 patient without hearing loss pre- treatment still had normal hearing after treatment and 1 patient's hearing was worse after treatment. Average follow-up was 21.3months.

CONCLUSIONS

Treatment of glomus tympanicum tumors by pre-operative embolization with ethanol and surgical resection has not been described before. Our results show that it is a safe procedure with a good long term tumor control, good clinical and audiological outcome.

Evaluation of Head and Neck Paragangliomas by Computed Tomography in Patients with Pheochromocytoma-Paraganglioma Syndromes

Background

Hereditary head and neck paragangliomas (HNP) are very often associated with pheochromocytoma-paraganglioma syndromes, which are caused by mutations in genes encoding subunits of succinate dehydrogenase (SDHx) complex.

The aim of this study was to determine the frequency and location of HNP among SDHx carriers.

Material/Methods

A total of 72 patients with SDHx mutations underwent computed tomography examinations of the head and neck. HNP were present in 44 (61.1%) out of 72 patients (31 SDHD, 11 SDHB, 2 SDHC); 113 HNP were found; the most common were carotid paragangliomas (59) and vagal paragangliomas (27).

Results

The HNP were statistically more frequent in carriers of SDHD mutations compared to carriers of SDHB mutations (72.1% vs. 43.5%, p=0.033). Multiple tumors more often occurred in patients with SDHD mutations 26/31 (83.9%) than in patients with SDHB mutations 6/11 (54.5%) p=0.05.

There was a significant difference in the prevalence of carotid paragangliomas between patients with SDHB and SDHD mutations (7/11 [63.6%] vs. 30/31 [96.8%], respectively, p=0.004). Patients with SDHD mutations more often had carotid paragangliomas located on the left side than on the right side, as compared to SDHB mutations 25/31 (80.6%) vs. 4/11 (36.4%), p=0.006.

Conclusions

SDHx mutations predispose to multifocal and bilateral HNP. Carotid and vagal paragangliomas occurred most often.

Patients with SDHD mutations are characterized by higher frequency of HNP than patients with SDHB mutations, which is mainly driven by higher frequency of carotid body tumors in patients with SDHD mutations. No difference in the frequency of head and neck paragangliomas in other locations was found.

Paragangliomas in patients with mutations of the SDHD gene

OBJECTIVE:

Paragangliomas represent neoplasms of neural crest origin that arise from paraganglia. Mutations in the gene encoding succinate dehydrogenase subunit D (SDHD) are responsible for a percentage of hereditary paragangliomas. We previously described a group of 271 pheochromocytoma patients, 11 of whom had mutations of the SDHD gene. The objective of this study was to find out whether those 11 patients had additional paragangliomas.

STUDY DESIGN:

Ten patients participated in our clinical screening program that included MRI of the skull base and neck, thorax, and abdomen, as well as an 18Fluoro-DOPA positron emission tomography (DOPA-PET).

RESULTS:

Five patients presented with head and neck paragangliomas, 1 patient with a thoracic paraganglioma, and 2 patients with intraabdominal paragangliomas.

CONCLUSIONS:

The screening for paragangliomas in patients with mutations of the SDHD gene offers the chance to diagnose those tumors in an early stage.

SIGNIFICANCE:

Because morbidity after surgical resection increases with tumor size, early surgery will minimize the potential risks.

Management of multicentric paragangliomas: Review of 24 patients with 60 tumors

BACKGROUND

The purpose of this study was to reflect our experience in the management of multicentric head and neck paragangliomas, including genetic study and counseling, diagnostic tools, types of treatment, and the need for monitoring.

METHODS

A retrospective review of 24 patients with multicentric paraganglioma, including a total of 60 paragangliomas: 37 carotid body tumors, 13 jugulotympanic paragangliomas, and 10 vagal paragangliomas.

RESULTS

A total of 26 surgical procedures were performed, including the resection of 36 paragangliomas. Four tumors were pending surgery at the time of this review. Radiotherapy was administered in 7 patients with 9 tumors. A "wait-and-scan" policy with periodic MRI imaging tests was instituted for 9 patients with 12 paragangliomas.

CONCLUSION

The knowledge of the different modalities of management is especially relevant in patients with multicentric paragangliomas. In every case, benefits and potential risks of all treatment options may be taken into consideration for every individual patient.

The presence of SDHB mutations should modify surgical indications for carotid body paragangliomas

OBJECTIVE

The aim of this study was to determine whether the genetic background of the disease should be incorporated into treatment decision making.

BACKGROUND

Carotid body paragangliomas are rare tumors that often affect patients with genetic mutations of the succinate dehydrogenase complex (SDHx). Despite growing evidence that germ line genetic mutations alter the aggressiveness of paragangliomas, treatment decisions are currently based only on clinical symptoms and tumor size in patients with carotid body paragangliomas.

METHODS

Retrospective analysis of 34 patients with carotid body paragangliomas who underwent genetic testing and surgical treatment. Recurrence was defined by the return of locoregional disease and/or development of distant metastases. Clinical characteristics and genetic testing results were analyzed as predictors of patient outcomes.

RESULTS

Thirty-four patients underwent 41 primary carotid body paraganglioma resections (median follow-up time of 42 months, range: 1-293). Overall survival was 91.2%. Twelve patients had germ line mutations in SDHB, 17 in SDHD, and 5 carried no known mutation. Surgical resection of larger tumors was associated with higher operative complications (odds ratio: 5.4, P = 0.05). Tumor size at resection was significantly smaller in patients with SDHB mutations than in patients with non-SDHB mutations (2.1 vs 3.3 cm, P = 0.02). Patients with a mutation in the SDHB gene also had significantly worse disease-free survival compared with patients without an SDHB gene mutation (P = 0.03).

CONCLUSIONS

Mutations in the SDHB gene are associated with worse disease-free survival after resection in patients with carotid body paragangliomas despite earlier intervention. This suggests that a more aggressive surgical approach is warranted in patients with SDHB mutations.

Genetics of hereditary head and neck paragangliomas

BACKGROUND

The purpose of this study was to give an overview on hereditary syndromes associated with head and neck paragangliomas (HNPGs).

METHODS

Our methods were the review and discussion of the pertinent literature.

RESULTS

About one third of all patients with HNPGs are carriers of germline mutations. Hereditary HNPGs have been described in association with mutations of 10 different genes. Mutations of the genes succinate dehydrogenase subunit D (SDHD), succinate dehydrogenase complex assembly factor 2 gene (SDHAF2), succinate dehydrogenase subunit C (SDHC), and succinate dehydrogenase subunit B (SDHB) are the cause of paraganglioma syndromes (PGLs) 1, 2, 3, and 4. Succinate dehydrogenase subunit A (SDHA), von Hippel-Lindau (VHL), and transmembrane protein 127 (TMEM127) gene mutations also harbor the risk for HNPG development. HNPGs in patients with rearranged during transfection (RET), neurofibromatosis type 1 (NF1), and MYC-associated factor X (MAX) gene mutations have been described very infrequently.

CONCLUSION

All patients with HNPGs should be offered a molecular genetic screening. This screening may usually be restricted to mutations of the genes SDHD, SDHB, and SDHC. Certain clinical parameters can help to set up the order in which those genes should be tested.

Paragangliomas and paraganglioma syndromes

Paragangliomas are rare tumors of neural crest origin. They are benign in the majority of cases and are characterized by a strong vascularisation.

In the head and neck region they most commonly occur as carotid body tumors. Jugulotympanic and especially vagal paragangliomas are seen less frequently. Complete surgical resection represents the only curative treatment option even though resection of locally advanced tumors regularly results in lesions of the lower cranial nerves and major vessels.

Appoximately 30% of all head and neck paragangliomas (HNPs) are hereditary and associated with different tumor syndromes. The paraganglioma syndromes 1, 3 and 4 (PGL 1, 3 and 4) make up the majority of those familial cases. PGL 1 is associated with mutations of the succinate dehydrogenase subunit D (SDHD) gene, PGL 3 is caused by SDHC and PGL 4 by SDHB gene mutations. Multiple HNPs and the occurance of HNPs together with pheochromocytomas are seen in SDHD as well as SDHB mutation carriers. In patients with SDHB mutations the risk for the development of malignant paraganglial tumors is significantly higher compared to SDHC and SDHD patients as well as patients with sporadic tumors. SDHC mutation carriers almost exclusively present with benign HNP that are unifocal in the majority of cases. The role of transmission is autosomal dominant for all three symptoms. Interestingly, there is a “parent-of-origin-dependent-inheritance” in subjects with SDHD gene mutations. This means that the disease phenotype may only become present if the mutation is inherited through the paternal line. We recommend screening for mutations of the genes SDHB, SDHC and SDHD in patients with HNPs. Certain clinical parameters can help to set up the order in which the three genes should be tested.

Solitary Paraganglioma of the Hypoglossal Nerve: Case Report

BACKGROUND AND IMPORTANCE:

We report the case history of solitary hypoglossal paraganglioma in a 64-year-old woman. The surgical difficulties encountered in the removal of this challenging tumor are discussed and as a literature review provided.

CLINICAL PRESENTATION:

A 64-year-old woman presented with a short history of dysphonia, occasional dysphagia, tinnitus, altered taste, and unilateral left-sided tongue wasting. On examination, there was left lower motor hypoglossal paralysis. Imaging showed a discrete enhancing lobulated mass, measuring 2 × 2 cm, in the region of the hypoglossal nerve extending into the hypoglossal canal suggestive of hypoglossal paraganglioma. A left dorsolateral suboccipital craniotomy was performed with the patient in the sitting position. The hypoglossal nerve appeared to be enlarged, and the jugular foramen was normal. Complete surgical debulking of the tumor was not attempted because of its vascular nature. The nerve was decompressed, and neuropathology confirmed a low-grade paraganglioma arising from the hypoglossal nerve. The patient was scheduled to receive stereotactic radiation for further management.

CONCLUSION:

When a case of solitary hypoglossal paraganglioma is encountered in clinical practice, the aim of management should be mainly focused on achieving a diagnosis and preserving the hypoglossal nerve function. If there is evidence of vascularity in the lesion noted on magnetic resonance imaging, a preoperative angiogram should be obtained with a view for embolization. We decompressed the hypoglossal canal and achieved good improvement in the patient's symptoms. We recommend stereotactic radiosurgery for remnant and small hypoglossal tumors and regular follow-up with magnetic resonance imaging scans.

Preoperative Angiography and Transarterial Embolization in the Management of Carotid Body Tumor: A Single-Center, 10-Year Experience

BACKGROUND:

Sixty percent of paragangliomas are located unilaterally at the carotid bifurcation. These are referred to as carotid body tumors (CBTs).

OBJECTIVE:

To present our 10-year experience in the management of patients with CBTs, and to evaluate the efficacy of angiography and preoperative embolization technique in this retrospective study.

METHODS:

Sixty-two patients with surgically removed CBTs (Shamblin class II and III), were divided into two groups. Group I, the preoperative embolization group, included 33 patients with 11 class II lesions and 25 class III lesions. Group II, the group that had surgery only, without preoperative embolization, included 29 patients with 9 class II lesions and 21 class III lesions. Comparisons were made between the groups in terms of mean intraoperative blood loss, mean operation time, mean postoperative hospital stay, and clinical complications.

RESULTS:

In group I, post-embolization angiography demonstrated complete tumor devascularization in 25 (76%) lesions and partial devascularization in 11 (24%) lesions. All but 1 (2%) lesion were completely excised. Mean intraoperative blood loss, mean operation time, and mean hospital stay were 354.8 ± 334.4 mL, 170.3 ± 75.4 min, 8.0 ± 2.1days in group I and 656.4 ± 497.4 mL, 224.6 ± 114.0 min, 9.5 ± 3.5days in group II, respectively. In group II, 27 lesions (91%) were completely removed. The transient ischemic attack (TIA) and cranial nerve injury incidence rates were 10.3% and 13.8% in group II and only 3% for TIA in group I.

CONCLUSION:

These results suggest angiography is highly valuable for the diagnosis of CBT. Preoperative selective embolization of CBT is an effective and safe adjunct for surgical resection, especially for Shamblin class II and III tumors.

Simultaneous aortic body tumor and pulmonary histiocytic sarcoma in a flat-coated retriever

A case of multiple primary tumors observed in the heart base and in the lung of a 7-year-old intact female, flat-coated retriever was reported. Morphological differences between both tumors and detailed immunohistochemical study revealed that the cardiac neoplasm was as a malignant aortic body tumor and the lung tumor was a pulmonary histiocytic sarcoma. The occurrence of aortic body tumor with other primary neoplasms has been previously reported in animals suggesting that this might be a common presentation in dogs.

Bilateral glomus tumor treated with PET-CT based conformal radiotherapy: a case report

Introduction

Glomus tumors are benign, slow growing tumors originating from paraganglionic tissue, mostly located at the carotid bifurcation, jugular foramen, cervical portion vagus nerve, and middle ear cavity. Radiotherapy is treatment of choice for patients with intracranial extension, and patients with bilateral and multiple tumors, or patients who are inoperable.

Case presentation

We present a 53-year-old female patient with a glomus tumor treated with positron emission tomography computed tomography planning and 3D conformal radiotherapy, and the patient has remained free of disease progression 2 years after.

Conclusion

It is suggested that radiotherapy is a good treatment modality in patients with glomus tumor, and metabolic imaging and treatment planning with positron emission tomography computed tomography is superior to other imaging modalities.

Head and neck paragangliomas in von Hippel-Lindau disease and multiple endocrine neoplasia type 2

BACKGROUND

Head and neck paragangliomas (HNPs) occur as sporadic or familial entities, the latter mostly in association with germline mutations of the SDHB, SDHC, or SDHD (SDHx) genes. Heritable non-SDHx HNP might occur in von Hippel-Lindau disease (VHL, VHL gene), multiple endocrine neoplasia type 2 (MEN2, RET gene), and neurofibromatosis type 1 (NF1, NF1 gene). Reports of non-SDHx HNP presentations are scarce and guidance for genetic testing nonexistent.

PATIENTS AND METHODS

An international consortium registered patients with HNPs and performed mutation analyses of the SDHx, VHL, and RET genes. Those with SDHx germline mutations were excluded for purposes of this study. Personal and family histories were evaluated for paraganglial tumors, for the major tumor manifestations, and for family history of VHL, MEN2, or NF1.

RESULTS

Twelve patients were found to have hereditary non-SDHx HNPs of a total of 809 HNP and 2084 VHL registrants, 11 in the setting of germline VHL mutations and one of a RET mutation. The prevalence of hereditary HNP is five in 1000 VHL patients and nine in 1000 non-SDHx HNP patients. Comprehensive literature review revealed previous reports of HNPs in five VHL, two MEN2, and one NF1 patient. Overall, 11 here presented HNP cases, and four previously reported VHL-HNPs had lesions characteristic for VHL and/or a positive family history for VHL.

CONCLUSIONS

Our observations provide evidence that molecular genetic testing for VHL or RET germline mutations in patients with HNP should be done only if personal and/or family history shows evidence for one of these syndromes.

[Diagnostic evaluation of temporal paragangliomas]

Paragangliomas are rare tumours deriving from paraganglia--small bodies of neuroendocrine tissue. Approximately 3% of paragangliomas occur in the head and neck area accounting for about 0,6% of all tumours of this region. Head and neck paragangliomas are divided into two groups: neck tumours (carotid body tumor and vagal paraganglioma) and temporal paragangliomas (jugular bulb tumor and tympanic paraganglioma). Temporal paragangliomas arise from paraganglia located in the petrous part of the temporal bone. Radiological evaluation of these lesions is essential for confirming the diagnosis and surgery planning. Most useful methods are magnetic resonance imaging and computed tomography. These modalities deliver important information about tumour location, extension and the state of the surrounding structures. Carotid angiography is a second step diagnostic method, performed in patients with jugular bulb paraganglioma. It has a diagnostic value and allows palliative or preoperative embolization of the tumor. Ultrasonographic evaluation and scintigraphy also provide advantages in diagnostic management.

Synchronous bilateral carotid body tumor and vagal paraganglioma: a case report and review of literature

We present a case of synchronous bilateral carotid body tumor and vagal paraganglioma in a 49-year-old man who presented with 3 months history of tenderness and palpable neck masses bilaterally. An encapsulated mass which was thought to be a carotid body tumor and an incidental 3 cm x 2 cm, 5 cm x 1 cm, 5 cm mass which seemed to be originated from vagus nerve were dissected from the left side. Pathology revealed carotid body tumor and vagal paraganglioma. Six months after the first operation, the carotid body tumor on the right side was totally excised. A discussion of this case is followed by a review of the literature surrounding this rare clinic and pathological entity.

Nasal paraganglioma: a case report

Paragangliomas are tumors of the autonomic nervous system, arising from paraganglionic tissue. Paragangliomas of the head and neck region are very rare. In the head and neck, the most common sites of origin of this neoplasm are the carotid body, the jugular bulb and the vagal body. Paragangliomas of the nose and paranasal sinuses are very uncommon. The authors referred one case of nasal paraganglioma in a 45-year-old male patient, who was submitted to surgical excision, and included clinical findings, diagnostic criteria, treatment, prognosis and literature review. The importance of reporting this case refers to the rare incidence of paragangliomas in the nasal cavity and paranasal sinuses.

Paraganglioma nasal: relato de caso

Paragangliomas são neoplasias que surgem a partir do tecido paragangliônico do sistema nervoso autônomo. Os paragangliomas da cabeça e pescoço são bastante raros. Os tipos mais freqüentemente encontrados são o carotídeo, o júgulo-timpânico e o vagal. Paragangliomas do nariz e dos seios paranasais são muito infreqüentes. Os autores descrevem um caso de paraganglioma nasal em um paciente do sexo masculino, com 45 anos de idade, que foi submetido à exérese da lesão, e relatam os achados clínicos, critérios diagnósticos, tratamento, prognóstico e revisão da literatura. Consideramos importante o relato deste caso em vista da raridade da localização nasal dos paragangliomas.

Paragangliomas of the head and neck: diagnosis and treatment

Paragangliomas of the head and neck (HNP) represent rare tumors of neural crest origin. They are highly vascular neoplasms that are benign in the majority of cases. The site of origin defines the name given those tumors. In the head and neck, they most commonly occur at the carotid bifurcation, where they are referred to as carotid body tumors (CBT). Other common sites of origin are the jugular bulb (jugular paraganglioma; JP), the tympanic plexus on the promontory (tympanic paraganglioma; TP) and the vagal nerve (vagal paraganglioma; VP). Patients with cervical paragangliomas frequently present with a painless, slowly enlarging mass in the lateral neck. In many patients with TP and JP, tinnitus and hearing loss are early symptoms. JP patients often suffer from lower cranial nerve deficits. Evaluation by an imaging modality is necessary to establish the diagnosis. Imaging procedures frequently used include B-mode sonography with color-coded Doppler sonography, computed tomography (CT), magnetic resonance imaging (MRI) and digital substraction angiography (DSA). Debate exists in the literature regarding the different treatment modalities for paragangliomas which include surgery, radiotherapy and stereotactic radiosurgery. The role of preoperative angiography and embolization has also been a matter of discussion. The diagnostic work up and the different treatment options for patients with head and neck paragangliomas will be presented and discussed.

The mitochondrial SDHD gene is required for early embryogenesis, and its partial deficiency results in persistent carotid body glomus cell activation with full responsiveness to hypoxia

The SDHD gene encodes one of the two membrane-anchoring proteins of the succinate dehydrogenase (complex II) of the mitochondrial electron transport chain. This gene has recently been proposed to be involved in oxygen sensing because mutations that cause loss of its function produce hereditary familiar paraganglioma, a tumor of the carotid body (CB), the main arterial chemoreceptor that senses oxygen levels in the blood. Here, we report the generation of a SDHD knockout mouse, which to our knowledge is the first mammalian model lacking a protein of the electron transport chain. Homozygous SDHD(-/-) animals die at early embryonic stages. Heterozygous SDHD(+/-) mice show a general, noncompensated deficiency of succinate dehydrogenase activity without alterations in body weight or major physiological dysfunction. The responsiveness to hypoxia of CBs from SDHD(+/-) mice remains intact, although the loss of an SDHD allele results in abnormal enhancement of resting CB activity due to a decrease of K(+) conductance and persistent Ca(2+) influx into glomus cells. This CB overactivity is linked to a subtle glomus cell hypertrophy and hyperplasia. These observations indicate that constitutive activation of SDHD(+/-) glomus cells precedes CB tumor transformation. They also suggest that, contrary to previous beliefs, mitochondrial complex II is not directly involved in CB oxygen sensing.

Case report: patient with multiple paragangliomas treated with long acting somatostatin analogue

Paragangliomas of the head and neck are uncommon neoplasms. They are usually benign, but tend to be locally invasive. Although surgical resection remains the definitive treatment, important issues about management arise when such lesions are inoperable. Beneficial effects of octreotide treatment have already been reported in a malign paraganglioma case. Here we report a 24 year old female with familial, bilateral, multiple paraganglioma in the head and neck region, who firstly presented with pulsatile tinnitus and hearing loss in her left ear. After embolization was performed, she underwent operation twice because of the gross tumor mass. No significant change in tumor size was determined after the operations, however there were no distant metastases. Although she experienced hypertension attacks, no hormonal overproduction was found in repeated measurements. As the tumor was unresectable, new alternative therapies were sought. Octreotide scintigraphy was positive in the tumoral tissue, so we began to treat her with somatostatin analogue octreotide. After a 16 month follow up period, an improvement of the performance status, the near normalisation of attacks and stabilization of tumor growth were achieved. However, in the last three visits, she began to experience symptoms more frequently and it had been necessary to increase the octreotide dose. She is now well and being followed up. In conclusion, the beneficial effects of octreotide treatment could be quantified by clinical, tumor and scintigraphic criteria. These data suggest that octreotide can be useful in the treatment of inoperable paragangliomas.

Multiple familial facial glomus: case report and review of the literature

Facial paraganglioma is an extremely rare tumor that originates from abnormal paraganglionic tissue situated in the intrapetrous facial canal. A review of the English-language literature shows that only 8 cases of facial nerve paraganglioma have been published. In each case the facial glomus presented itself sporadically, completely independent of any other form of paraganglioma. This study reports an intrapetrous facial glomus that occurred in a case of multiple paragangliomas with a hereditary pattern. To our knowledge, this is the first report of such a combination.

Etiopathogenesis and clinical presentation of carotid body tumors

The carotid body (CB) is a highly specialized small organ located at the bifurcation of the common carotid artery in the neck and plays an important role in acute adaptation to hypoxia. The most common diseased state of the carotid body is its enlargement (i.e., the CB paraganglioma), which can be caused by a genetic predisposition (hereditary paraganglioma, PGL) and by chronic hypoxic stimulation. The CB is the most common tumor site in head and neck paragangliomas. Currently, inactivating germline mutations in the mitochondrial complex II subunits SDHB, SDHC, and SDHD have been identified as genetic risk factors for CB tumors (CBTs). Another locus at chromosome 11q13, identified by linkage analysis in a single family, may harbor a fourth susceptibility gene. Although CBTs are mostly slow-growing and benign, they can cause significant morbidity because of their proximity to major arteries and nerves in the head and neck. Here, we review the etiological factors implicated in the development of CBTs and provide information pertaining to their clinical presentation. Although CBTs are rare, they have the potential to provide unique insights for tumorigenesis and oxygen sensing and signaling mechanisms.

Hereditary paraganglioma targets diverse paraganglia

Paragangliomas are highly vascularised and often heritable tumours derived from paraganglia, a diffuse neuroendocrine system dispersed from skull base to the pelvic floor. The carotid body, a small oxygen sensing organ located at the bifurcation of the carotid artery in the head and neck and the adrenal medulla in the abdomen, are the most common tumour sites. It now appears that mutations in SDHB, SDHC, and SDHD, which encode subunits of mitochondrial complex II (succinate dehydrogenase; succinate-ubiquinone oxidoreductase), are responsible for the majority of familial paragangliomas and also for a significant fraction of non-familial tumours. Germline mutations in complex II genes are associated with the development of paragangliomas in diverse anatomical locations, including phaeochromocytomas, a finding that has important implications for the clinical management of patients and genetic counselling of families. Consequently, patients with a paraganglioma tumour, including phaeochromocytoma, and a complex II germline mutation should be diagnosed with hereditary paraganglioma, regardless of family history, anatomical location, or multiplicity of tumours. This short review attempts to bring together relevant genetic data on paragangliomas with a particular emphasis on head and neck paragangliomas and phaeochromocytomas.

Combined endovascular and surgical treatment of head and neck paragangliomas--a team approach

BACKGROUND

Paragangliomas are highly vascular tumors of neural crest origin that involve the walls of blood vessels or specific nerves within the head and neck. They may be multicentric, and they are rarely malignant. Surgery is the preferred treatment, and these tumors frequently extend to the skull base. There has been controversy concerning the role of preoperative angiography and embolization of these tumors and the benefits that these procedures offer in the evaluation and management of paragangliomas.

METHODS

Forty-seven patients with 53 paragangliomas were treated from the period of 1990-2000. Initial evaluation usually included CT and/or MRI. All patients underwent bilateral carotid angiography, embolization of the tumor nidus, and cerebral angiography to define the patency of the circle of Willis. Carotid occlusion studies were performed with the patient under neuroleptic anesthesia when indicated. The tumors were excised within 48 hours of embolization.

RESULTS

Carotid body tumors represented the most common paraganglioma, accounting for 28 tumors (53%). All patients underwent angiography and embolization with six patients (13%), demonstrating complications (three of these patients had embolized tumor involving the affected nerves). Cerebral angiography was performed in 28 patients, and 5 of these patients underwent and tolerated carotid occlusion studies. The range of mean blood loss according to tumor type was 450 to 517 mL. Postoperative cranial nerve dysfunction depended on the tumor type resected. Carotid body tumor surgery frequently required sympathetic chain resection (21%), with jugular and vagal paraganglioma removal frequently resulting in lower cranial nerve resection. These patients required various modes of postoperative rehabilitation, especially vocal cord medialization and swallowing therapy.

CONCLUSIONS

The combined endovascular and surgical treatment of paragangliomas is acceptably safe and effective for treating these highly vascular neoplasms. Adequate resection may often require sacrifice of one or more cranial nerves, and appropriate rehabilitation is important in the treatment regimen.

Head and neck paragangliomas: an overview

Paragangliomas of the head and neck are unique tumors. Their pathology, tissue of origin, location, genetics, potential for bio-chemical activity, multicentricity, and growth pattern are unusual compared with more common head and neck tumors. Because these tumors are widespread and can appear in the ear, neck, larynx, nose, orbit, and chest, they cross subspecialties of otolaryngology.

Genetics of familial paragangliomas: past, present, and future

Genetic studies of hereditary paraganglioma tumors could increase the understanding of the biology of these fascinating tumors, with important clinical implications for diagnosis and treatment. This article focuses on the genetics of paraganglioma tumors, with limited reference to their general morphologic and clinical aspects. The paraganglioma tumor phenotype is defined. The genetic and physical mapping studies recently performed are summarized--studies that eventually led to the discovery of the gene for hereditary paraganglioma type 1 (PGL1). Finally, future directions stemming from the PGL gene discovery are described.