Octreotide Scintigraphy for the Detection of Paragangliomas

False Identity: Lymphoid Hyperplasia Imitating a Large Paraganglioma

The danger of the parapharyngeal space mass comes from the small space and vital neighboring structures. Its differential diagnosis is broad, however benign lymphoid hyperplasia in this region has not been previously reported. The clinical presentation, imaging, surgical findings and pathology slides were reviewed in an adult patient with a parapharyngeal space mass. The literature on somatostatin-positive parapharyngeal space lesions was reviewed. A 51-year old male with otalgia for 3 months, hearing loss, and tinnitus underwent audiogram, revealing asymmetric hearing loss. Laryngoscopy demonstrated a paretic true vocal cord. Subsequent MRI demonstrated 4.5 cm post-styloid parapharyngeal space mass displacing the carotid artery anterolaterally. Octreoscan scan showed significant uptake of the somatostatin analog. Angiogram showed prominent vascular blush. The mass was excised transcervically and histopathology demonstrated lymphoid hyperplasia. This case demonstrates that post-styloid parapharyngeal masses may be lateral retropharyngeal nodes. An octreotide-positive lymphoid hyperplasia has never been previously reported.

Glomus tumors of the head and neck: thirteen years' institutional experience and management

Background: Head and neck paragangliomas are slowly growing benign tumors and they originate from specialized neural crest cells. Aims/objectives: This study aimed to express the safety of paraganglioma surgery regarding complications, treatment, and outcomes of patients with head and neck glomus tumors. Materials and methods: Medical records of patients who were operated because of head and neck paraganglioma between 2006 and 2016 were reviewed. Results: The study group consisted of 49 patients (M/F: 6/43). The patients were distributed as follows: 22 glomus caroticum (GC) (44.8%), 8 glomus jugulare (GJ) (16.3%), 10 glomus tympanicum (GT) (20.4%), 4 glomus vagale (GV) (8.1%), 2 GC + GV (4%), 2 bilateral GC (4%) and 1 thyroidal glomus tumor (2%). All GC and GV tumors were resected via cervical approach. Three of GJ tumors were resected through transmastoid approach while five of them were resected through both transmastoid and cervical approach. Nine GT tumors were resected via transmastoid approach. One patient received cyberknife. Thyroid paraganglioma was diagnosed incidentally after total thyroidectomy. Mean follow-up period was 61.92 ± 35.11 months (1-124 m). Conclusions and significance: The choice of treatment depends on the size, location and biologic activity of tumor as well as the physical condition of the patient. Our results show that glomus tumors can be resected with low mortality and morbidity rates due to developing imaging and microsurgical methods.

European Association of Nuclear Medicine Practice Guideline/Society of Nuclear Medicine and Molecular Imaging Procedure Standard 2019 for radionuclide imaging of phaeochromocytoma and paraganglioma

PURPOSE

Diverse radionuclide imaging techniques are available for the diagnosis, staging, and follow-up of phaeochromocytoma and paraganglioma (PPGL). Beyond their ability to detect and localise the disease, these imaging approaches variably characterise these tumours at the cellular and molecular levels and can guide therapy. Here we present updated guidelines jointly approved by the EANM and SNMMI for assisting nuclear medicine practitioners in not only the selection and performance of currently available single-photon emission computed tomography and positron emission tomography procedures, but also the interpretation and reporting of the results.

METHODS

Guidelines from related fields and relevant literature have been considered in consultation with leading experts involved in the management of PPGL. The provided information should be applied according to local laws and regulations as well as the availability of various radiopharmaceuticals.

CONCLUSION

Since the European Association of Nuclear Medicine 2012 guidelines, the excellent results obtained with gallium-68 (68Ga)-labelled somatostatin analogues (SSAs) in recent years have simplified the imaging approach for PPGL patients that can also be used for selecting patients for peptide receptor radionuclide therapy as a potential alternative or complement to the traditional theranostic approach with iodine-123 (123I)/iodine-131 (131I)-labelled meta-iodobenzylguanidine. Genomic characterisation of subgroups with differing risk of lesion development and subsequent metastatic spread is refining the use of molecular imaging in the personalised approach to hereditary PPGL patients for detection, staging, and follow-up surveillance.

Lateral ectopic thyroid mimics carotid body tumor on Indium-111 pentetreotide scintigraphy

A 34-year old woman with past history of anxiety, depression, and hypothyroidism resulting from prior total thyroidectomy for multinodular goiter presented with complaints of palpitations, sweating, and tachycardia. Clinical examination revealed a painless right lateral neck mass. USG/CT of the neck revealed the soft tissue mass located at the right carotid bifurcation. A subsequent Indium-111 pentetreotide somatostatin receptor scintigraphy (SRS) demonstrated tracer uptake in the mass. Hence, secretory carotid body tumor/paraganglioma was strongly suspected. However, post-surgical histopathological specimen revealed only benign thyroid follicles indicative of lateral ectopic thyroid with no evidence of neuroendocrine cells or malignancy. This case highlights the importance of considering lateral ectopic thyroid, a very rare entity, in the differential diagnosis for carotid bifurcation masses. Also highlighted is the false positivity from normal but ectopic thyroid tissue on Indium-111 pentetreotide SRS mimicking a paraganglioma.

Recent advances in the imaging of pheochromocytomas and paragangliomas

Pheochromocytoma and paraganglioma (PPGL) belong to the family of neural crest cell-derived neoplasms, and can be widely distributed throughout the body. Over the past few years, with respect to these tumors, precision medicine has offered the promise of improved patient care. Through tumor visualization and identification of molecular signatures, nuclear medicine is capable of playing a key role in PPGL precision medicine. 68Ga-labeled somatostatin analogs were found to improve the detection and staging of head and neck paragangliomas, SDHx-related PPGLs and metastatic PPGLs regardless of genetic background. For PPGLs associated with increased kinase signaling or HIF2A mutations, 18F-fluorodihydroxyphenylalanine appears to be the most informative radiopharmaceutical. This review emphasizes the current theranostic approaches and future perspective related to PPGL imaging options.

Vagal Paraganglioma Presenting as a Neck Mass Associated with Cough on Palpation

A 70-year-old female presented with a neck mass and sporadic dry cough, often leading to fits of coughing severe enough to cause vomiting. The patient reported that touching the mass triggered the cough. On examination, a 2.5 cm right-sided level two neck mass deep to the sternocleidomastoid was present. Palpation of the mass immediately triggered coughing. Cross-sectional imaging proposed vagal paraganglioma as the chief differential, which was confirmed following surgical excision. The patient reported complete resolution of her severe dry cough after surgery. Vagal paragangliomas are rare neuroendocrine tumors arising from the neural crest-derived paraganglionic tissue surrounding the vagus nerve, typically presenting as a neck mass associated with hoarseness or pulsatile tinnitus. To the best of our knowledge this is a unique description in the English literature. This case is presented to aid physicians should they encounter a neck mass associated with cough. Vagal paraganglioma, although rare, should be part of the differential in such a presentation.

Imaging innovations in temporal bone disorders

The development of new imaging techniques coupled with new treatment algorithms has created new possibilities in treating temporal bone diseases. This article provides an overview of recent imaging innovations that can be applied to temporal bone diseases. Topics covered include the role of magnetic resonance (MR) diffusion-weighted imaging in cholesteatomas and skull base epidermoids, whole-body molecular imaging in paragangliomas of the jugular foramen, and MR arterial spin labeling perfusion for dural arteriovenous fistulas and arteriovenous malformations.

Neuroendocrine tumors: beyond the abdomen

Several classification systems for neuroendocrine tumors (NETs) exist, which use variable terminology and criteria for grading and staging. This variability in terminology can cause confusion and difficulty in recognizing which tumors are, in fact, members of this heterogeneous group of malignancies. The largest group of NETs, the gastroenteropancreatic NETs, has been well described and characterized; however, there are less-recognized extra-abdominal NETs that can arise from nearly any organ in the body. In this article, the clinical features and imaging appearances of the extra-abdominal NETs will be reviewed, compared, and contrasted. This diverse group consists of paragangliomas, Merkel cell carcinomas, esthesioneuroblastomas, NETs of the lung, and medullary thyroid carcinomas. Recognition of these tumors as part of the larger group of NETs is important for understanding how best to approach imaging for their diagnosis, staging, and potential treatment. Familiarity with the computed tomographic and magnetic resonance imaging appearances and the role of radionuclide imaging of these heterogeneous groups aids in the correct diagnosis and in treatment planning.

Current approaches and recent developments in the management of head and neck paragangliomas

Head and neck paragangliomas (HNPGLs) are rare neuroendocrine tumors belonging to the family of pheochromocytoma/paraganglioma neoplasms. Despite advances in understanding the pathogenesis of these tumors, the growth potential and clinical outcome of individual cases remains largely unpredictable. Over several decades, surgical resection has long been the treatment of choice for HNPGLs. However, increasing experience in various forms of radiosurgery has been reported to result in curative-like outcomes, even for tumors localized in the most inaccessible anatomical areas. The emergence of such new therapies challenges the traditional paradigm for the management of HNPGLs. This review will assist and guide physicians who encounter patients with such tumors, either from a diagnostic or therapeutic standpoint. This review will also particularly emphasize current and emerging knowledge in genetics, imaging, and therapeutic options as well as the health-related quality of life for patients with HNPGLs.

Endocrine scintigraphy with hybrid SPECT/CT

Nuclear medicine imaging of endocrine disorders takes advantage of unique cellular properties of endocrine organs and tissues that can be depicted by targeted radiopharmaceuticals. Detailed functional maps of biodistributions of radiopharmaceutical uptake can be displayed in three-dimensional tomographic formats, using single photon emission computed tomography (CT) that can now be directly combined with simultaneously acquired cross-sectional anatomic maps derived from CT. The integration of function depicted by scintigraphy and anatomy with CT has synergistically improved the efficacy of nuclear medicine imaging across a broad spectrum of clinical applications, which include some of the oldest imaging studies of endocrine dysfunction.

Complex glomus jugulare tumor: management issues

Glomus tumors are rare and locally aggressive, vascular paragangliomas of the skull base. Tumors may progress to cause lower cranial nerve palsies and involve the major vascular structure in the skull base, and thus pose very difficult surgical challenges. One such case is presented, the management problems in such "complex glomus jugulare" tumors are discussed, and the literature reviewed.

Current and future trends in the anatomical and functional imaging of head and neck paragangliomas

Head and neck paragangliomas (HNPGLs) account for approximately 3% of all paragangliomas (PGLs). Most often, HNPGLs are benign, nonsecreting, and slowly progressing. The initial physical examination and biochemical diagnosis usually adds very little to the proper diagnosis of these tumors, and, therefore, radiologists and nuclear medicine physicians play a pivotal role in providing the initial diagnosis, the locoregional staging, and the plan for detecting potential multicentric or metastatic lesions. Based on several current studies, the most accurate use of HNPGL-specific initial and subsequent imaging modalities must be guided by the knowledge of genetics and the specifically measured biochemical profile of these tumors for the proper management of these patients. Thus, this short review article presents the application of the most up-to-date anatomical and functional imaging approaches to HNPGLs tightly linked to the clinical management of these patients. Based on the most recent studies, 18F-FDOPA PET/CT has been shown to be a useful addition to anatomical imaging in the preoperative localization and molecular assessment of HNPGLs. It is estimated that the frequency of metabolically active PGLs on 18F-FDOPA PET/CT in this region is higher than 90%. For patients with hereditary PGL syndromes, (18)F-FDG-PET/CT should be reserved. Imaging of somatostatin receptors using Octreoscan or 68Ga-labeled somatostatin analogues plays an important role for selecting patients for targeted radiation therapy. This review also concludes that it is expected that in the near future, these patients will indeed benefit from new diagnostic approaches based on the identification of new targets by molecular profiling studies that will result in the development of novel PGL-specific radiopharmaceuticals.

EANM 2012 guidelines for radionuclide imaging of phaeochromocytoma and paraganglioma

PURPOSE

Radionuclide imaging of phaeochromocytomas (PCCs) and paragangliomas (PGLs) involves various functional imaging techniques and approaches for accurate diagnosis, staging and tumour characterization. The purpose of the present guidelines is to assist nuclear medicine practitioners in performing, interpreting and reporting the results of the currently available SPECT and PET imaging approaches. These guidelines are intended to present information specifically adapted to European practice.

METHODS

Guidelines from related fields, issued by the European Association of Nuclear Medicine and the Society of Nuclear Medicine, were taken into consideration and are partially integrated within this text. The same was applied to the relevant literature, and the final result was discussed with leading experts involved in the management of patients with PCC/PGL. The information provided should be viewed in the context of local conditions, laws and regulations.

CONCLUSION

Although several radionuclide imaging modalities are considered herein, considerable focus is given to PET imaging which offers high sensitivity targeted molecular imaging approaches.

Updated and new perspectives on diagnosis, prognosis, and therapy of malignant pheochromocytoma/paraganglioma

Malignant pheochromocytomas/paragangliomas are rare tumors with a poor prognosis. Malignancy is diagnosed by the development of metastases as evidenced by recurrences in sites normally devoid of chromaffin tissue. Histopathological, biochemical, molecular and genetic markers offer only information on potential risk of metastatic spread. Large size, extraadrenal location, dopamine secretion, SDHB mutations, a PASS score higher than 6, a high Ki-67 index are indexes for potential malignancy. Metastases can be present at first diagnosis or occur years after primary surgery. Measurement of plasma and/or urinary metanephrine, normetanephrine and metoxytyramine are recommended for biochemical diagnosis. Anatomical and functional imaging using different radionuclides are necessary for localization of tumor and metastases. Metastatic pheochromocytomas/paragangliomas is incurable. When possible, surgical debulking of primary tumor is recommended as well as surgical or radiosurgical removal of metastases. I-131-MIBG radiotherapy is the treatment of choice although results are limited. Chemotherapy is reserved to more advanced disease stages. Recent genetic studies have highlighted the main pathways involved in pheochromocytomas/paragangliomas pathogenesis thus suggesting the use of targeted therapy which, nevertheless, has still to be validated. Large cooperative studies on tissue specimens and clinical trials in large cohorts of patients are necessary to achieve better therapeutic tools and improve patient prognosis.

Contemporary nuclear medicine imaging of neuroendocrine tumours

Neuroendocrine tumours (NETs) are rare, heterogeneous, and often hormonally active neoplasms. Nuclear medicine (NM) imaging using single photon- and positron-emitting radiopharmaceuticals allows sensitive and highly specific molecular imaging of NETs, complementary to anatomy-based techniques, such as computed tomography (CT) and magnetic resonance imaging (MRI). Somatostatin-receptor scintigraphy is a whole-body imaging technique widely used for diagnosis, staging and restaging of NETs. The increasing availability of hybrid single-photon emission CT (SPECT)/CT cameras now offers superior accuracy for localization and functional characterization of NETs compared to traditional planar and SPECT imaging. The potential role of positron-emission tomography (PET) tracers in the functional imaging of NETs is also being increasingly recognized. In addition to 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG), newer positron-emitting radiopharmaceuticals such as (18)F-dihydroxyphenylalanine (DOPA) and (68)Ga-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) peptides, show promise for the future. This article will summarize the role of current and emerging radiopharmaceuticals in NM imaging of this rare but important group of tumours.

Classification and management of cervical paragangliomas

INTRODUCTION

Cervical paragangliomas are slow-growing tumours that eventually cause lower cranial nerve palsies and infiltrate the skull base. Surgical treatment may cause the same deficits and, in some, risks more serious neurological deficits. We describe a classification used to guide investigation, consent and management of cervical paragangliomas based on extensive experience.

METHODS

The case notes of patients managed by the senior author at a tertiary referral skull base unit between 1987 and 2010 were reviewed retrospectively. A total of 87 cervical paragangliomas were identified in 70 patients (mean age: 46 years, range: 13-77 years). Of these, 35 patients had 36 vagal paragangliomas, 43 patients had 50 carotid body paragangliomas and 8 had both. One cervical paraganglioma arose from neither the carotid body nor the nodose ganglion. The main outcome measures were death, stroke, gastrostomy and tracheotomy.

RESULTS

All tumours were classified pre-operatively based on their relationship to the carotid artery, skull base and lower cranial nerves. Type 1 tumours were excised with a transcervical approach, type 2 with a transcervical-parotid approach and type 3 with a combined transcervical-parotid and infratemporal fossa approach. Type 4 patients underwent careful assessment and genetic counselling before any treatment was undertaken. There were no peri-operative deaths; two patients had strokes, one required a long-term feeding gastrostomy and none required a tracheotomy.

CONCLUSIONS

The use of a pre-operative classification system guides management and surgical approach, improves accuracy of consent, facilitates audit and clarifies which patients should be referred to specialised centres.

Synchronous malignant vagal paraganglioma with contralateral carotid body paraganglioma treated by radiation therapy

Paragangliomas are rare tumors and very few cases of malignant vagal paraganglioma with synchronous carotid body paraganglioma have been reported. We report a case of a 20-year old male who presented with slow growing bilateral neck masses of eight years duration. He had symptoms of dysphagia to solids, occasional mouth breathing and hoarseness of voice. Fine needle aspiration cytology (FNAC) performed where he lived showed a sinus histiocytosis and he was administered anti-tubercular treatment for six months without any improvement in his symptoms. His physical examination revealed pulsatile, soft to firm, non-tender swellings over the anterolateral neck confined to the upper-mid jugulo-diagastric region on both sides. Direct laryngoscopy examination revealed a bulge on the posterior pharyngeal wall and another over the right lateral pharyngeal wall. Magnetic resonance imaging (MRI), 99mTc-labeled octreotide scan and angiography diagnosed the swellings as carotid body paraganglioma, stage III on the right side with left-sided vagal malignant paraganglioma. Surgery was ruled out as a high morbidity with additional risk to life was expected due to the highly vascular nature of the tumor. The patient was treated with radiation therapy by image guided radiation to a dose of 5040cGy in 28 fractions. At a follow-up at 16 months, the tumors have regressed bilaterally and the patient can take solids with ease.

A clinical overview of pheochromocytomas/paragangliomas and carcinoid tumors

Pheochromocytomas/paragangliomas are rare tumors; most are sporadic. Biochemical proof of disease is better with measurement of plasma metanephrines and less cumbersome than determinations in urine; its implementation is expanding. Anatomical imaging with computed tomography or magnetic resonance imaging should be followed by functional (nuclear medicine) imaging: chromaffin tumor-specific methods are preferred. Treatment is surgical; for nonoperable disease other options are available. Overall 5-year survival is 50%. Carcinoid tumors derive from serotonin-producing enterochromaffin cells in the fore-, mid- or hindgut. Biochemical screening (and follow-up) is done with measurements of 5-hydroxyindoloacetic acid in urine. For most carcinoids, functional imaging is better than other modalities in localizing primary tumors. Surgery is the treatment of choice; nonresectable tumors are treated with somatostatin analogs or chemotherapy. Overall 5-year survival for patients with carcinoids is 67%.

Systematic screening and treatment evaluation of hereditary neck paragangliomas

Familial paragangliomas of the neck are often bilateral and more aggressive than spontaneous forms. Tumors appear earlier (2nd-4th decade) often with diffuse, multifocal involvement. Without treatment, these tumors can lead to significant morbidity. Three families with succinate dehydrogenase subunit D (SDHD) germline mutations underwent clinical and genetic evaluation. Patients were screened using ultrasound and evaluated further with conventional and functional imaging. Tumors with a diameter >1.5 cm were surgically removed. Multicentric and bilateral tumors were detected in 9/13 (69%) and 8/13 (62%) patients, respectively. Surgical morbidity occurred in 64% of patients. Local recurrence was 57%, although this was lower in tumors with a diameter <2 cm. We recommend an algorithm for a systematic approach to the diagnosis, monitoring, and treatment of familial head and neck paragangliomas. Operative treatment in advanced stages often leads to unwanted morbidity, such that earlier detection and treatment of smaller tumors seems to be of benefit.

Temporal paragangliomas

Temporal paragangliomas (PGL) are usually limited to the paraganglionar system with a sporadic or familial origin. Familial PGL have recently been shown to be associated with germline alterations in SDH group of genes, and occasionally are associated with a variety of genetic multisystemic disorders (von Hippel-Lindau disease, multiple endocrine neoplasia type 2 and neurofibromatosis type 1). Temporal bone PGL are normally located in the region of the jugular foramen and on the promontory along the Jacobson nerve. Occasionally, vagal PGL may reach the jugular foramen and behave as jugular PGL. Treatment of temporal PGL must be based on the biological behavior of the tumour, age and medical condition of the patient, location and size of the PGL, and potential for treatment induced morbidity. The main treatment modalities for PGL are surgery and radiation therapy. Patients with large temporal PGL whose resection would result in potentially disabling morbidity are often selected for radiation therapy or wait and scan policy. Small tympanic PGL where resection may be carried out with a low morbidity risk can be removed through an endomeatal tympanotomy. Jugular PGL limited to the infralabyrinthine region involving only the vertical segment of the ICA, can benefit of an extended facial recess approach, which allows a postoperative normal hearing and facial nerve function. For more extensive disease in the middle ear or around the ICA, external auditory canal preservation is not possible and some kind of facial nerve mobilization is required. Preservation of lower cranial nerves is facilitated by intrabulbar dissection, previous extradural ligation of the sigmoid sinus. Management of large intracranial involvement is controversial, although most authors advocate resection of the tumour in a single stage. Surgical control of the tumour can be expected in 70-85% of the patients and is clearly dependent on the tumour stage. Tumour size determines success in hearing and lower cranial nerves preservation.

Pheochromocytoma: Physiopathologic Implications and Diagnostic Evaluation

Pheochromocytoma (PHEO) is a chromaffin cell tumor embryologically arising from the neural crest tissue. The dominant secretory products of PHEO are catecholamines: noradrenaline (norepinephrine), adrenaline (epinephrine), and to a lesser extent dopamine. In addition to catecholamines, PHEO cells also elaborate and release several neuropeptides and inflammatory cytokines which can exert intra-adrenal and extra-adrenal systemic effects and cause characteristic clinical syndromes. In a concise review we present the intra-adrenal and extra-adrenal pathophysiologic implications of PHEO and the nuclear medicine modalities that permit functional imaging of physiological processes and help localize these tumors. The specific pathways of synthesis, metabolism, and inactivation of catecholamines (of PHEOs and paragangliomas) can be used as means to develop suitable tracers for positron emission tomography (PET) ligands. In this review we focus on imaging with PET using [(18)F]-fluorodopamine, [(18)F]-fluorohydroxyphenylalanine, [(11)C]-epinephrine, or [(11)C]-hydroxyephedrine and examine how functional imaging can often complement traditional anatomical imaging modalities and other scintigraphic techniques.

Current Trends in Functional Imaging of Pheochromocytomas and Paragangliomas

Most pheochromocytomas/paragangliomas should be evaluated with anatomical imaging (computed tomography or magnetic resonance imaging) followed by functional imaging (nuclear medicine modalities). Functional imaging assures that the tumor is indeed a pheochromocytoma/paraganglioma and enables more thorough localization, especially detecting as many lesions as possible (in particular for metastatic disease). Functional imaging for pheochromocytomas/paragangliomas, can use radiolabeled ligands specific for pathways of synthesis, metabolism, and inactivation of catecholamines or nonspecific ligands. In an overview of the available nuclear medicine modalities, we summarize the accumulated experience and recommend when functional imaging should be applied to patients with pheochromocytoma/paraganglioma.

Tumours of familial origin in the head and neck

Individuals with inherited cancer syndromes are at significant risk of developing both benign and malignant tumours as a result of a germline mutation in a specific tumour suppressor gene. Tumours of familial origin are a rare event in the head and neck but despite this, they deserve a growing interest. Familial paragangliomas are most of the time limited to the paraganglionar system, but also may be part of different syndromic associations. Since early detection of paragangliomas reduces the incidence of morbidity and mortality, genotypic analysis in the search of SDHB, SDHC and SDHD mutations in families of affected patients plays a front-line diagnostic role, leading to more efficient patient management. Multiple endocrine neoplasias type 1 are characterized by the simultaneous occurrence of at least two of the three main related endocrine tumours: parathyroid, enteropancreatic and anterior pituitary. These tumours arise from inactivating germline mutations in the MEN-1 gene. No clear correlation of MEN-1 genotype with genotype has emerged to date, and MEN-1 mutation testing in tumours is not used clinically because it have not implications for tumour staging. Multiple endocrine neoplasia type 2 is due to a germline mutation in the RET proto-oncogene. Hallmarks of MEN-2A (the commonest phenotypic variant) include medullary thyroid carcinoma, pheochromocytoma, and hyperparathyroidism. The most central clinical difference with MEN-1 is that the associated cancer can be prevented or cured by early thyroidectomy in mutation carriers. Individuals with neurofibomatosis type 1 present early in life with pigmentary abnormalities, skinfold freckling and iris hamartomas, as result of NF1 gene mutation. Neurofibromatosis 2 is caused by inactivating mutations of the NF2 gene, and is characterized by the development of nervous system tumours (mainly bilateral vestibular schwannomas), ocular abnormalities, and skin tumours. The molecular genetic basis of nasopharyngeal carcinomas remains unknown, but there is evidence for the linkage of these tumours to chromosome 3p. Finally, the high rate of p16 mutations in squamous cell carcinomas and the association of p16 with familial melanoma propose p16 as an ideal candidate gene predisposing to familial squamous cell carcinomas. The elucidation of the cellular processes affected by dysfunction in familial tumours of the head and neck may serve to identify potential targets for future therapeutic interventions.

Cervical Paraganglioma Mimicking a Parathyroid Adenoma on Tc-99m Sestamibi Scintigraphy

A 32-year-old man with a clinical and biochemical profile suggestive of primary hyperparathyroidism presented with a soft tissue mass on the left side of the neck. Multiphasic planar and SPECT Tc-99m sestamibi (MIBI) scintigraphy showed focally increased tracer concentration in the mass. Subsequent histopathology and immunostaining identified the mass as a parathyroid hormone-secreting cervical paraganglioma, indicating that this tumor should be considered in the differential interpretation of MIBI concentration in the neck.

New functional imaging modalities for chromaffin tumors, neuroblastomas and ganglioneuromas

Nuclear medicine modalities use radiolabeled ligands that either follow metabolic pathways or act on cellular receptors. Thus, they permit functional imaging of physiological processes and help to localize sites such as tumors that harbor pathological events. The application of positron emission tomography (PET) ligands to the specific pathways of synthesis, metabolism and inactivation of catecholamines found in chromaffin tumors, neuroblastomas and ganglioneuromas can be used to provide a more thorough localization of these types of tumor. Recent advances have been made in functional imaging to localize pheochromocytomas, paragangliomas, neuroblastomas and ganglioneuromas, including approaches based on PET with [(18)F]fluorodopamine, [(18)F]fluorohydroxyphenylalanine, [(11)C]epinephrine or [(11)C]hydroxyephedrine. Such functional imaging can complement computed tomography or magnetic resonance imaging and other scintigraphic techniques to localize these tumors before surgical or medical therapeutic approaches are considered.

The basic science of glomus jugulare tumors

Glomus tumors are a fascinating group of lesions. It is a challenge for neurosurgeons and otolaryngologists to resect them completely with minimal morbidity. Laboratory researchers have discovered extremely interesting genetic and molecular biology factors involved in the development and growth of glomus tumors. In this article the author reviews the genetics, protein mutations, angiogenesis and apoptosis associated with tumor formation, and the secretion of vasoactive substances is discussed as well. It is hoped that with further research less invasive measures may be developed to treat these tumors.

Secreting vagal paraganglioma

Paragangliomas are rare tumors that derive from neural crest tissue. Vagal paragangliomas account for only 3% of all head and neck paragangliomas. Patients with vagal paragangliomas typically present with an asymptomatic neck mass and, less frequently, with cranial neuropathies. It is estimated that only 1% to 3% of all head and neck paragangliomas secrete catecholamines. The incidence of secreting vagal paragangliomas is even smaller. The diagnosis of a secreting paraganglioma involves the use of a screening test for serum catecholamines and a 24-hour urinary test for catecholamine metabolites. The identification and staging of these tumors can be performed through the use of MRI and/or CT scans and an octreotide scintigraphy. The mainstay treatment is surgical extirpation; however, preoperative medical blockade is critical to avoid a hypertensive crisis intra-operatively. We present two illustrative cases of secreting vagal paragangliomas involving a complex diagnostic and therapeutic algorithm.

Octreotide scintigraphy in the detection of recurrent paragangliomas

OBJECTIVE

Conventional follow-up of surgically and radiotherapy-treated paragangliomas is usually carried out with physical examinations and either magnetic resonance imaging and/or computed tomography. Up to now, octreotide has been reserved for primary diagnosis, for which it has been shown to be a reliable imaging modality. However, the postsurgical and postradiation changes seen on conventional imaging make the diagnosis of small recurrent lesions difficult. We sought to evaluate the role of octreotide scintigraphy in the detection of recurrent paragangliomas.

STUDY DESIGN

We based this case series on 3 patients who were found to have recurrent paragangliomas after primary surgical resection. All patients underwent octreotide scintigraphy during routine follow-up.

RESULTS

Three patients were found to have recurrent paragangliomas using octreotide scintigraphy. In one of the patients, conventional imaging (magnetic resonance imaging, computed tomography) failed to detect the recurrence.

CONCLUSION

The octreotide study was able to detect the small recurrences because octreotide binds directly to receptors on the tumor and is not affected by postsurgical or postradiotherapy changes. The intrinsic resolution of most commercially available gamma cameras is about 1 cm, making it quite sensitive to detect small tumors. Although this patient did not have synchronous lesions, octreotide scintigraphy can also aide in the detection of such lesions.

Octreotide scintigraphy in the head and neck

OBJECTIVES/HYPOTHESIS

Octreotide is a somatostatin analogue that, when coupled to a radioisotope, produces a scintigraphic image of neuroendocrine tumors (NET) expressing somatostatin type 2 receptors (SSR 2). Octreotide scintigraphy (OS) may be useful in confirming the preoperative diagnosis of certain head and neck NET. Paragangliomas (PG), like many NET, have been found to have a high density of SSR 2 on the cell surfaces. Other NET of the head and neck include merkel cell carcinomas (MCC), medullary thyroid carcinomas (MTC), and esthesioneuroblastomas.

STUDY DESIGN

A retrospective study that compared the results of OS with the histopathologic diagnosis in 74 patients with head and neck NET.

RESULTS

Of the 60 patients undergoing evaluation for suspected paraganglioma, OS was correctly positive in 36 of the 37 patients with PG. OS was correctly negative in 19 of the 23 patients that did not exhibit PG. For PG, this yielded a sensitivity of 97% and a specificity of 82%. There were 14 patients in the nonparaganglioma group. OS detected or diagnosed all metastases in three patients with MTC, locoregional recurrences in two patients with esthesioneuroblastoma, an extrapituitary adenoma in one patient, and metastasis in two patients with MCC. It failed to detect a paraspinal metastasis in the third patient with MCC.

CONCLUSION

On the basis of this series of patients, OS appears to be a reliable test to detect PG and may be helpful in detecting primary and metastatic disease for NET.

Pediatric extraadrenal paraganglioma

BACKGROUND

Pediatric paraganglioma is rare and extraadrenal paraganglioma has not been characterized in children.

METHODS

The authors reviewed the medical records and pathology samples of children with extraadrenal paraganglioma treated at our institution between December 1978 and September 2000. Clinical presentation, treatment, and outcome were evaluated.

RESULTS

Eight patients (median age, 11.4 years) were identified, 4 were boys and none had a family history of paraganglioma or associated syndromes. Primary tumors arose in the retroperitoneum (n = 3), carotid body (n = 2), jugulotympanic ganglion (n = 1), cervical-paraspinal region (n = 1), and lung (n = 1). Extraadrenal paraganglioma had not been suspected at presentation in any patient. Of 5 patients who underwent gross total resection at the time of diagnosis, 4 remain disease free, 1 had microscopic residual tumor and died of disease. Three patients had initially unresectable disease, 2 are disease free after neoadjuvant therapy and delayed surgery, and 1 has persistent disease after tumor embolization and radiotherapy.

CONCLUSIONS

Pediatric extraadrenal paraganglioma occurs most commonly in the retroperitoneum and head and neck, and the diagnosis usually is not suspected at the time of presentation. Surgery is the mainstay of treatment, and outcome is good after gross total resection. Neoadjuvant therapy can facilitate complete resection of initially unresectable tumors.

An unusual case of complete Carney's triad in a 14-year-old boy

Carney's triad represents the association of gastric gastrointestinal stromal tumor, pulmonary chondroma, and extraadrenal paraganglioma. Only 79 cases of this rare condition have been described. Here, the authors describe the unusual case of a 14-year-old boy who presented with a complete Carney's triad. This is only the second reported case in the world literature of a patient manifesting a complete Carney's triad at presentation. The management of each tumor is discussed.

Head and neck paragangliomas: physiology and biochemistry

Paragangliomas of the head and neck are derivatives of neural crest cells, comprising part of the diffuse neuroendocrine system. Indeed, paragangliomas encompass a unique subset of tumors of the head and neck. Their biochemistry and physiology are similar to other neuroendocrine tumors unlike tumors based on location. This article discusses their distinct biologic attributes.

Radiographic evaluation and assessment of paragangliomas

Radiographic imaging plays an important role in the diagnosis and treatment of paragangliomas. Diagnosis and treatment should be performed as a team effort, with all the involved disciplines working together to provide the best possible individualized work-up and treatment plan for the patient.

Genetic analysis in the diagnosis of familial paragangliomas

OBJECTIVES

In the management of two related patients with multicentric glomus jugulare tumors, given the incidence of 1:30,000 with approximately 20% familial cases, our objective was to review the genetic characteristics and inheritance patterns of these tumors and to determine what molecular genetic screening possibilities exist for the phenotypically normal family members. In addition, our aim was to review the incidence of various multicentric paraganglioma (PGL) tumor location combinations.

METHODS

Molecular genetic linkage analysis testing was performed on the 2 patients and 14 other unaffected family members. We report the results of this screening and review the literature on the incidence and genetics of paragangliomas.

RESULTS

The inheritance pattern in the literature demonstrates autosomal dominant transmission with maternal imprinting (inactivation). The proclivity for multicentric origin increases to 26% in familial cases, as reflected in our patients. In addition to the two patients, four unaffected family members demonstrated the presence of the disease haplotype at chromosome band 11q23, which indicates a very high likelihood of developing a paraganglioma, given the highly penetrant nature of the disease.

CONCLUSIONS

It is clear that the familial PGL gene locus is situated at chromosome 11q23. The gene itself and its exact degree of penetrance, however, still await identification. Since early detection of paragangliomas reduces the incidence of morbidity and mortality, genotypic analysis as a screening tool in families of affected patients should play a front-line diagnostic role, leading to more timely and cost-effective patient management.