MRI screening of kindred at risk of developing paragangliomas: support for genomic imprinting in hereditary glomus tumours

A Study of Paraganglioma Cases With Non-European Ancestry

Capable of generating excess catecholamines, untreated extra-adrenal paragangliomas (PGLs) result in severe cardiovascular morbidity and mortality. Increasingly, a hereditary basis can be identified to underlie PGLs, though such data are largely absent in populations of non-European descent. We present two patients with PGL, both exhibiting similar age, sex, and geographic ancestry. Our patients are unrelated, Kinyarwanda-speaking females from the Democratic Republic of the Congo. The first patient presented with lower extremity edema and poorly controlled hypertension and was found to have multifocal PGL in the abdomen and bladder, proven by biopsy and treated with surgical excision. Our second patient presented with palpitations, shortness of breath, headache, and hypertension, was found to have mediastinal PGL, and underwent surgical excision. Genetic testing was negative in both cases. The first patient has not shown recurrence based on active surveillance with imaging and biochemical testing. There is a concern for recurrence in the second patient, eight years after diagnosis, which is currently being investigated. Our second patient lived at a high altitude for most of her life, pointing toward a possible role of hypoxia in the pathogenesis of her tumor development. Our cases raise questions that require active inquiry regarding additional environmental and/or genetic factors that might predispose to PGLs in uncommon anatomic sites and in understudied, vulnerable populations.

Clinical management of paragangliomas

Paragangliomas (PGLs) are rare vascular, neuroendocrine tumors of paraganglia, which are associated with either sympathetic tissue in adrenal (pheochromocytomas (PCCs)) and extraadrenal (sympathetic paraganglioma (sPGLs)) locations or parasympathetic tissue of the head and neck paragangliomas (HNPGLs). As HNPGLs are usually benign and most tumors grow slowly, a wait-and-scan policy is often advised. However, their location in the close proximity to cranial nerves and vasculature may result in considerable morbidity due to compression or infiltration of the adjacent structures, necessitating balanced decisions between a wait-and-see policy and active treatment. The main treatment options for HNPGL are surgery and radiotherapy. In contrast to HNPGLs, the majority of sPGL/PCCs produces catecholamines, in advanced cases resulting in typical symptoms and signs such as palpitations, headache, diaphoresis, and hypertension. The state-of-the-art diagnosis and localization of sPGL/PCCs are based on measurement of plasma and/or 24-h urinary excretion of (fractionated) metanephrines and methoxytyramine (MT). sPGL/PCCs can subsequently be localized by anatomical (computed tomography and/or magnetic resonance imaging) and functional imaging studies (123I-metaiodobenzylguanidine-scintigraphy, 111In-pentetreotide scintigraphy, or positron emission tomography with radiolabeled dopamine or dihydroxyphenylalanine). Although most PGL/PCCs are benign, factors such as genetic background, tumor size, tumor location, and high MT levels are associated with higher rates of metastatic disease. Surgery is the only curative treatment. Treatment options for patients with metastatic disease are limited. PGL/PCCs have a strong genetic background, with at least one-third of all cases linked with germline mutations in 11 susceptibility genes. As genetic testing becomes more widely available, the diagnosis of PGL/PCCs will be made earlier due to routine screening of at-risk patients. Early detection of a familial PGL allows early detection of potentially malignant PGLs and early surgical treatment, reducing the complication rates of this operation.

Laryngeal paraganglioma: a rare clinical entity managed by supraselective embolization and lateral pharygotomy

Laryngeal paragangliomas are benign slow growing tumors with symptoms resembling squamous cell carcinoma. Hoarseness or dysphasia are the commonest presenting symptoms and usually it presents as an submucosal mass on laryngoscopy. Ninety percentage of these tumors occur in the supraglottic larynx and the rest in the glottis and the subglottic region. Functional activity is seen in a few (2.9 %), none are associated with paraneoplastic syndromes. A 35-year-old male presented to us with hoarseness of voice since 4 months duration. Contrast arteriography demonstrated that the left superior thyroid artery supplied >80 % of the blood supply to the laryngeal mass. Supraselective embolization was done from the right femorals under local anaesthesia and sedation which was uneventfull. The tumor was excised from lateral pharyngotomy approach with an partial laryngectomy procedure. Microscopy and immune-histochemistry confirmed it to be paraganglioma. Complete surgical resection or partial laryngectomy with meticulous dissection of surrounding tissues and preservation of neurovascular structures gives an excellent prognosis as far as oncological clearance is concerned. Malignant paragangliomas of the larynx are rare and an major meta-analysis is necessary to provide a true biological behaviour of this tumor.

The Dutch founder mutation SDHD.D92Y shows a reduced penetrance for the development of paragangliomas in a large multigenerational family

Germline mutations in SDHD predispose to the development of head and neck paragangliomas, and phaeochromocytomas. The risk of developing a tumor depends on the sex of the parent who transmits the mutation: paragangliomas only arise upon paternal transmission. In this study, both the risk of paraganglioma and phaeochromocytoma formation, and the risk of developing associated symptoms were investigated in 243 family members with the SDHD.D92Y founder mutation. By using the Kaplan-Meier method, age-specific penetrance was calculated separately for paraganglioma formation as defined by magnetic resonance imaging (MRI) and for paraganglioma-related signs and symptoms. Evaluating clinical signs and symptoms alone, the penetrance reached a maximum of 57% by the age of 47 years. When MRI detection of occult paragangliomas was included, penetrance was estimated to be 54% by the age of 40 years, 68% by the age of 60 years and 87% by the age of 70 years. Multiple tumors were found in 65% and phaeochromocytomas were diagnosed in 8% of paraganglioma patients. Malignant paraganglioma was diagnosed in one patient (3%). Although the majority of carriers of a paternally inherited SDHD mutation will eventually develop head and neck paragangliomas, we find a lower penetrance than previous estimates from studies based on predominantly index cases. The family-based study described here emphasizes the importance of the identification and inclusion of clinically unaffected mutation carriers in all estimates of penetrance. This finding will allow a more accurate genetic counseling and warrants a 'wait and scan' policy for asymptomatic paragangliomas, combined with biochemical screening for catecholamine excess in SDHD-linked patients.

A multidisciplinary approach to carotid paragangliomas

The surgical management of carotid paragangliomas can be problematic. A multidisciplinary approach was used to include vascular surgery, otolaryngology, and neuroradiology to treat these patients over 9 years. From January 1992 to July 2001, a multidisciplinary team evaluated patients with carotid paragangliomas. Analyzed patient data included age, gender, diagnostic evaluation, tumor size, preoperative tumor embolization, operative exposure, need for extracranial arterial sacrifice/reconstruction, postoperative morbidity including cranial nerve dysfunction, and long-term follow-up. Twenty-five carotid paragangliomas in 20 patients underwent multidisciplinary evaluation and management. Average age was 51 years (range, 28-83 years), and 52% were male. Diagnostic evaluation included computed tomography in 76%, magnetic resonance imaging/magnetic resonance angiography in 52%, catheter angiography in 60%, and duplex ultrasonography in 16%. An extended neck exposure was required in 11 cases (44%), mandibulotomy was used once (4%), and mandibular subluxation was never required. The external carotid artery (ECA) was sacrificed in 8 cases (32%). The carotid bifurcation was resected in 1 patient (4%) requiring interposition reconstruction of the internal carotid artery. Preoperative tumor embolization was performed for 13 tumors (52%). Operative blood loss for patients undergoing preoperative embolization (Group I) was comparable to the nonembolized group (group II): group I lost 365 +/-180 mL versus 360 +/- 101 mL for group II (P = .48). This occurred despite larger tumors (group I - 4.2 cm versus group II - 2.1 cm, P = .03) and a higher mean Shamblin class (group I - 2.5 versus group II - 1.45, P = .001) for group I. There were no perioperative mortalities. Transient cranial nerve dysfunction occurred in 13 CBTs (52%), 2 (8%) of which remained present after 4 months. Patients with carotid paragangliomas benefit from a multidisciplinary team approach. Neuroradiology has been used for selective preoperative embolization, which has decreased estimated blood loss during excision of larger complex tumors. A combined surgical team of otolaryngology and vascular surgery provides for exposure of the distal internal carotid artery as high as the skull base, limited permanent cranial nerve dysfunction, and selective early division and excision of the external carotid artery for complete tumor resection.

Familial paraganglioma and gastric stromal sarcoma: a new syndrome distinct from the Carney triad

Paragangliomas may be inherited in an autosomal dominant manner either alone (as in PGL1, PGL2, and PGL3 syndromes) or as a component of a multiple tumor syndrome (as in von Hippel-Lindau disease and neurofibromatosis type 1). In this article, we describe 12 patients (7 male and 5 female) with an average age of 23 years from five unrelated families that manifested paraganglioma and gastric stromal sarcoma; the tumors were inherited in an apparent autosomal dominant manner, with incomplete penetrance. Seven patients had paraganglioma, four had paraganglioma and gastric stromal sarcoma, and one had gastric stromal sarcoma. The paraganglioma was multicentric and the gastric stromal sarcoma multifocal. Because of the rarity of gastric stromal sarcoma and its multifocality, the young age of the patients, and the unlikelihood of coincidental co-occurrence of paragangliomas and gastric stromal sarcomas, we suggest that a new syndrome exists with these two main components, a condition that is familial and distinct from the Carney triad.

Assessment of a potential tumor-seeking manganese metalloporphyrin contrast agent in a mouse model

The performance of a newly developed potential tumor-seeking magnetic resonance (MR) contrast agent alpha-Aqua-13,17-bis(1-carboxypropionyl) carbamoylethyl-3,8-bis(1-phenethyloxyethyl)-beta-hydroxy-2,7,12,18-tetramethyl-porphyrinato manganese (III) (HOP-8P) was tested using a mouse model. Tumor-bearing (SCC-VII) mice were imaged using a 1.5T MR imager before and after intravenous administration of 0.1 mmol/kg of HOP-8P. A biodistribution analysis was performed using an optical emission spectrometer. Significant enhancement of the transplanted tumor was observed in MR images 24 h after intravenous injection of HOP-8P. The biodistribution assessment of manganese also correlated with the results of the imaging study. During the 24-h period following contrast administration, HOP-8P was consistently cleared from the circulation, liver, kidneys, and muscle; however, it was progressively accumulated within the tumor. HOP-8P is a promising tumor-seeking metalloporphyrin MR contrast agent with a wide imaging window.

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.

Proportion of heritable paraganglioma cases and associated clinical characteristics

OBJECTIVE/HYPOTHESIS

To determine the heritable proportion of paraganglioma (PGL) and identify clinical features associated with heritable PGL.

STUDY DESIGN

Patients diagnosed with head and neck PGLs, identified retrospectively through clinical otolaryngology practices and/or participation in previous PGL research studies, were given a medical and family history questionnaire.

METHODS

Questionnaire information was used to classify participants as having "heritable" or "non-heritable" cases of PGL. Classification of the participants identified through otolaryngology clinics was used to estimate the heritable proportion of PGL. Statistical analysis was performed to identify significant differences in the clinical characteristics of the heritable versus non-heritable groups.

RESULTS

Among the otolaryngology clinic population, 35% were classified as having heritable PGL. Individuals with heritable PGL were younger on average than those with non-heritable PGL. The majority of non-heritable participants were female, but there was an equal gender ratio among the heritable participants. Individuals diagnosed with a carotid body tumor (CBT) were 5.8 times more likely to be classified as heritable than those diagnosed with PGL at other anatomic locations.

CONCLUSIONS

Approximately 35% of individuals who present to an otolaryngologist with a head and neck PGL have inherited a predisposition for this growth. Among individuals diagnosed with head and neck PGL, those diagnosed with CBT are 5.8 times more likely to have an inherited predisposition than those diagnosed with PGL at other anatomic locations.

Novel mutations and the emergence of a common mutation in the SDHD gene causing familial paraganglioma

Familial paragangliomas (PGL) are slow-growing, highly vascular, generally benign neoplasms, usually of the head and neck, that arise from neural crest cells. This rare autosomal dominant disorder is highly penetrant and influenced by genomic imprinting through paternal transmission. Timely detection of these tumors may afford the affected individual the opportunity to avoid the potential serious morbidity associated with surgical removal and the mortality that may accompany local and distant metastases. Linkage to two distinct chromosomal loci, 11q13.1 and 11q23, has been previously reported. Recently, germline mutations in SDHD, a mitochondrial complex II gene on chromosome 11q23, have been demonstrated. We evaluated members of seven families with PGL, five previously studied and shown to have linkage to chromosome 11q23. The entire coding region of the SDHD gene was sequenced and yielded four novel mutations and one mutation shared in three of our unrelated families. Novel mutations found included a truncating mutation in exon 2, as well as a missense mutation, a deletion, and an insertion in exon 4. Three of our families had a common mutation in exon 3 (P81L) that has been reported and thought to be a founder mutation. A restriction enzyme assay was developed for initial screening of this mutation. Molecular analysis is now available and recommended for presymptomatic diagnosis in those at-risk individuals and for confirmatory diagnosis in those having PGL.

Sympathetic paraganglioma as an unusual cause of Horner's syndrome

BACKGROUND

Paragangliomas are rare tumors arising from paraganglionic tissue of neural crest origin. They are present in any location where autonomic ganglia are found. The most common location in the head and neck is the carotid body, followed by the jugular bulb and vagus nerve.

METHODS

A 30-year-old woman with a slowly growing left neck mass, aniscoria, and left eyelid ptosis was found to have a vascular tumor consistent with a paraganglioma arising near the left carotid bifurcation. After preoperative embolization, the patient underwent resection of the tumor.

RESULTS

The tumor was found to be arising from the left sympathetic trunk and did not involve any other surrounding structures. Histopathologic analysis revealed the typical findings of a paraganglioma.

CONCLUSIONS

Sympathetic paragangliomas are exceedingly rare tumors in the head and neck and should be considered in the differential diagnosis when clinical and radiographic evidence suggest a paraganglioma. The presentation is typically a slow-growing neck mass with the presence of an ipsilateral Horner's syndrome.

Baroreflex failure syndrome after bilateral excision of carotid body tumors: an underestimated problem

Carotid body tumors (CBTs) are relatively rare paragangliomas that develop from neural crest cells at the bifurcation of the common carotid artery. They are generally slow growing and benign. Excision is currently considered the treatment of choice, although vascular and especially neural injuries are still relatively frequent in patients with large or bilaterally resected tumors. The baroreflex failure syndrome (BFS) has recently been identified as a severe, rarely recognized, and certainly underestimated complication after the bilateral excision of CBTs. The present report describes a case of a bilateral CBT followed by BFS and reviews the experiences reported in the literature. In light of the low incidence of malignancy of these tumors, their biologic behavior, their very high rate of cranial nerve palsy, and the occurrence of BFS in bilaterally resected paragangliomas, the current practice of bilaterally removing these tumors is questioned.

From the archives of the AFIP. Paragangliomas of the head and neck: radiologic-pathologic correlation. Armed Forces Institute of Pathology

Paragangliomas of the head and neck are ubiquitous in their distribution, originating from the paraganglia or glomus cells within the carotid body, vagal nerve, middle ear, jugular foramen, and numerous other locations. The typical patient is middle-aged and presents late in the course of the disease, with a painless slow-growing mass. Clinical manifestations include hoarseness of voice, lower cranial nerve palsies, pulsatile tinnitus, and other neuro-otologic symptoms. The overall prognosis of patients with a cervical paraganglioma is favorable, whereas its temporal bone counterpart often results in recurrence, residual tumor, and neurovascular compromise when in the advanced stage. Pathologic examination reveals a characteristic biphenotypic cell line, composed of chief cells and sustentacular cells with a peripheral fibrovascular stromal layer that are organized into a whorled pattern ("zellballen"). Imaging hallmarks of paragangliomas of the head and neck include an enhancing soft-tissue mass in the carotid space, jugular foramen, or tympanic cavity at computed tomography; a salt-and-pepper appearance at standard spin-echo magnetic resonance imaging; and an intense blush at angiography. Imaging studies depict the location and extent of tumor involvement, help determine the surgical approach, and help predict operative morbidity and mortality. Surgical treatment is definitive. Radiation treatment is included as a palliative adjunct for the exceptional paraganglioma not amenable to surgery.

A new observation of the Carney's triad with long follow-Up period and additional tumors

The etiology of the Carney's triad (gastrointestinal stromal tumors, pulmonary chondromas, and paragangliomas) is unknown, and only 57 cases have been reported since its identification in 1977. We report the clinical course of a female with the complete triad and some additional tumors. Bilateral vagal paragangliomas were treated surgically and with radiotherapy between the ages of 24 and 26 years. Subsequently she underwent surgery for a gastric leiomyosarcoma (27 years), a pleomorphic adenoma of the parotid gland (49 years) and a multifocal breast cancer with axillary spread (50 years). A calcified lesion was also noticed in the left lung, the radiologic diagnosis of which was consistent with chondroma. A mediastinal paraganglioma, detected at 56 years on a control X-ray of the chest, was partially excised at 63 years. At the last control, performed at 66 years, the patient was alive with residual cervical and mediastinal paraganglioma. Her younger brother was affected by Hirschsprung's disease and died at 54 years of rectal cancer. Her daughter is 33 and has been suffering since birth with severe constipation. In conclusion, this is one of the longest followed-up patients with Carney's triad. Her case illustrates the need for early recognition of the setting in order to detect the component tumors at a stage when surgery may be curative, and careful and life-long follow-up, both because the multicentricity of the classic components tends to manifest metachronously and because of the tendency to develop other tumors, some of which may be malignant. Furthermore, the presence of Hirschsprung's disease in the patient's family, coupled with the alleged common origin of two component lesions from derivatives of the neural crest, open new avenues for the understanding of this disorder.

Hereditary paraganglioma

Head and neck paraganglioma is a rare tumour, especially in its familial form. We report a case of a multifocal head and neck paraganglioma in a young man with a family history of cervical tumours. At the age of 24, exploration of a left cervical swelling disclosed jugulotympanic and carotid body paragangliomas. Surgical removal of both tumours was performed. Two years later, a right carotid body as well as vagal paragangliomas were discovered. Follow-up at age 30 demonstrated relapse of the bilateral cervical paragangliomas, but also aortopulmonary and mesogastric paragangliomas. Cervical paragangliomas were also detected in the patient's sister and daughter, but not in his father. Furthermore, the proband's paternal grandmother and a maternal great-uncle had a history of 'neck scar'. This family history is suggestive of an autosomal dominant pattern of inheritance with maternal genomic imprinting. Genetic analysis of paraganglioma kindreds showed linkage with two different loci: 11q13.1 and 11q22.3-q23. Further knowledge of the genes involved could provide early diagnosis and accurate genetic counselling in affected families. Thorough familial investigation is consequently mandatory in all head and neck paragangliomas, especially in younger patients with multiple localizations, as surgical removal is safer at an early stage.

Gastric stromal sarcoma, pulmonary chondroma, and extra-adrenal paraganglioma (Carney Triad): natural history, adrenocortical component, and possible familial occurrence

OBJECTIVE

To investigate the natural history of the triad of gastric stromal sarcoma, pulmonary chondroma, and extra-adrenal paraganglioma, a rare syndrome of unknown cause primarily affecting young women.

METHODS

Mayo Clinic records, the world literature, and the author's files were searched for patients with all or 2 of the 3 tumors.

RESULTS

Seventy-nine patients, 67 women and 12 men, were identified, 17 (22%) with the 3 tumors and 62 (78%) with 2 tumors. Forty-two (53%) had gastric and pulmonary tumors, the most common combination. The longest interval between detection of the first and second components was 26 years (mean, 8.4 years; median, 6 years). Follow-up ranged from 1 year to 49 years (mean, 20.6 years; median, 20 years). Sixty-four patients (81%) were alive, 19 (24%) apparently free of disease and 45 (57%) with residual or metastatic tumors. Thirty-two patients (41%) had had 1 or more local recurrences of the gastric sarcoma; the longest interval to first recurrence was 36 years. Twenty-one survivors (27%) had hepatic metastatic gastric sarcoma with follow-up of 1 year to 25 years (mean, 9.3 years; median, 7 years). Fifteen patients (19%) were dead, 10 (13%) of whom died of the disorder. Ten patients (13%) had nonfunctioning adrenocortical tumors. Two patients each had a sibling with 1 component of the triad.

CONCLUSIONS

The triad is a chronic, persistent, and indolent disease. Benign adrenocortical tumors are a component of the condition. The disorder may be familial.

Familial carotid body paragangliomas and sensorineural hearing-loss: a new syndrome

BACKGROUND

Carotid body paragangliomas are rare tumors that are sometimes familial, the transmission of which is thought to be by genomic imprinting. We have treated a family who exhibited co-inheritance of carotid body paraganglioma and sensorineural hearing-loss, a relationship that has not been previously reported.

METHODS

We studied a large Australian family who exhibited familial carotid body paragangliomas, many of whose members also suffered tinnitus or hearing-loss. This relationship was examined by reviewing the medical records of family members with confirmed tumors, carrying out neck ultrasonic scanning or computed tomography on their relatives to look for previously unrecognized tumors, and arranging audiometric testing. This information was used to characterize the type of hearing-loss present in this family and to construct a pedigree for the two traits.

RESULTS

The hearing-loss observed in this family was sensorineural in character. Of 15 family members studied over four generations, eight were confirmed positive for both carotid body paraganglioma and sensorineural hearing-loss, two for the tumor only (one of whom did not have his hearing assessed) and one for hearing-loss alone. Four family members were negative for both traits.

CONCLUSIONS

The pedigree provides evidence of a previously undescribed association between familial carotid body paraganglioma and sensorineural hearing-loss, a combination that appears to be co-inherited in this family.

Founder effect at PGL1 in hereditary head and neck paraganglioma families from the Netherlands

PGL1, a gene responsible for hereditary paragangliomas of the head and neck, recently was mapped to a 2-cM interval on chromosome 11q22-q23, by linkage and haplotype-sharing analysis of a large multibranch Dutch family. We determined the disease-linked haplotype, as defined by 13 markers encompassing a large interval on 11q21-q23, in 10 additional families ascertained from the same geographical locale. Alleles were identical for six contiguous markers, spanning a genetic distance of 6 cM and containing PGL1. Despite this strong indication of a common ancestor, no kinships between the families could be demonstrated through genealogical surveys going back to 1800 a.d. We conclude that a single ancestral mutation is responsible for most, if not all, hereditary paragangliomas, in this region of The Netherlands, and that strong founder effects may exist at the PGL1 locus.

111Indium pentetreotide scan detection of familial paragangliomas

Approximately 10% of head and neck paragangliomas are familial. Magnetic resonance imaging (MRI) is reported to be the best method for screening these families. 111Indium pentetreotide (Octreoscan) scintigraphy has been shown to be a sensitive indicator of neural crest tumors such as paragangliomas. Early diagnosis and treatment of familial paragangliomas (FP) would decrease the morbidity of tumor excision. Patients from two kindred with FP were scanned 24 hours after intravenous injection with approximately 6 millicuries of 111Indium pentetreotide. The entire body was imaged. Areas of increased uptake were further imaged with MRI. Altogether, five patients had positive 111Indium pentetreotide scans. Two unsuspected glomus tympanicums and bilateral carotid body tumors were identified. Three people tested had no abnormal uptake. There were no untoward reactions to the nuclide. 111Indium pentetreotide scanning is a safe, noninvasive method for early diagnosis of FP and is useful in detecting multicentric lesions. Patients suspect for FP are undergoing 111Indium pentetreotide imaging and followed up with MRI of the involved site if positive.

Color Doppler imaging of paragangliomas in the neck

PURPOSE

In this study, we describe the color Doppler imaging findings in carotid body tumors and vagal body tumors.

METHODS

B-mode and color Doppler imaging were performed on 17 patients who had a total of 25 previously diagnosed paragangliomas (14 carotid body tumors and 11 vagal body tumors).

RESULTS

Nineteen of 25 tumors were depicted. Five small vagal body tumors in the region of the nodose ganglion and 1 carotid body tumor could not be depicted. With B-mode imaging, paragangliomas appeared as well-defined, solid, hypoechoic masses. With color Doppler imaging, hypervascularity with a low-resistance flow pattern was demonstrated in all but 1 of the 19 tumors.

CONCLUSIONS

The use of color Doppler imaging in the workup of an ambiguous neck mass is advocated.

Familial paragangliomas: linkage to chromosome 11q23 and clinical implications

Familial paragangliomas (PGL), or glomus tumors, are slow-growing, highly vascular, generally benign neoplasms usually of the head and neck that arise from neural crest cells. This rare autosomal-dominant disorder is highly penetrant and influenced by genomic imprinting through paternal transmission. Timely detection of these tumors affords the affected individual the opportunity to avoid the potential morbidity associated with surgical removal, and mortality that may accompany local and distant metastases. Linkage to two distinct chromosomal loci, 11q13.1 and 11q22.3-q23, has been reported, suggesting heterogeneity. We evaluated three multigenerational families with hereditary PGL, including 19 affected, and 59 unaffected and potentially at-risk individuals. Numerous microsatellite markers corresponding to each candidate region were tested in all members of the three families. Confirmation of linkage to 11q23 was established in all three families. The inheritance pattern was consistent with genetic imprinting. Using these data, we were able to provide presymptomatic diagnosis with subsequent removal of tumor from one individual, and to start several others on an MRI surveillance protocol.

First experiences with genetic counselling based on predictive DNA diagnosis in hereditary glomus tumours (paragangliomas)

Hereditary glomus tumour (MIM 168,000) or paraganglioma (PGL) is a slowly progressive disorder causing benign tumour growth predominantly in the head and neck region. Though benign in nature the tumours can lead to severe morbidity. Inheritance of PGL is autosomal dominant and is strongly modified by genomic imprinting; only a paternally transmitted PGL gene leads to symptoms. A gene for PGL has recently been mapped to 11q22.3-q23. Genetic counselling on the basis of DNA linkage diagnosis was offered in an extended Dutch pedigree. Thirty-two subjects opted for further counselling, of whom 20 applied for DNA testing and participated in a standardised protocol. Sixteen cases had presymptomatic testing (paternal allele); four of these appeared to have the at risk haplotype and in two of them a glomus tumour was subsequently detected on MRI. In one case linkage results were inconclusive (recombination) and one person did not want to learn his test result. Four cases had testing for carrier status (maternal allele) of which one appeared to be a carrier. Our data show that genetic counselling gains significant accuracy when based on parent of origin, sex of the counsellee, and DNA linkage diagnosis. Moreover, a normal DNA result may prevent unnecessary worry and investigations, while an established presymptomatic diagnosis will guide adequate clinical management. The psychological impact of counselling and predictive DNA testing is unclear as yet. Further investigations into the natural history of PGL in gene carriers and into the psychological impact of DNA testing is desirable.

A 15-year experience with chemotherapy of patients with paraganglioma

BACKGROUND

Paraganglioma is a rare tumor thought to arise from the neuroectodermally derived paraganglionic cells that are dispersed widely along the autonomic ganglia. They can metastasize to bones, lymph nodes, and lungs and occasionally present with spinal cord compression. Up to 60% of retroperitoneal paragangliomas can be functional, with symptoms and signs of norepinephrine overproduction.

METHOD

A 15-year experience with chemotherapy of patients with paraganglioma was reviewed. The patient population was identified through a search of the data-base maintained by the Departments of Melanoma-Sarcoma Medical Oncology and Pathology at the University of Texas M.D. Anderson Cancer Center (Houston, TX).

RESULTS

Thirteen of 84 patients with histologically confirmed diagnosis of paraganglioma were treated with chemotherapy. The median age was 42 years (range, 25-67 years); there were eight males and five females. Primary sites included retroperitoneum (seven patients), head and neck (two patients), pelvis, bladder, mediastinum, and paravertebral (one patient each). Twelve patients received chemotherapy for metastatic disease, and 1 had an unresectable mediastinal primary tumor. Eleven patients received cyclophosphamide, doxorubicin, and DTIC/dacarbazine (CyADIC)/cyclophosphamide, vincristine, doxorubicin and DTIC/dacarbazine (CyVADIC), and 2 received doxorubicin and dacarbazine (ADIC) at standard doses for a median of 4 cycles (range, 2-12 cycles). Six of 13 patients achieved an objective partial remission (response rate = 46%, 95% confidence interval = 19-73%); 6 other patients had stable disease, and one developed progressive disease. At the time of last follow-up, eight patients were alive with disease, four died, and one patient was alive with no evidence of disease. The median follow-up from diagnosis was 45 months (range, 12-300 months).

CONCLUSION

Cyclophosphamide, doxorubicin, dacarbazine chemotherapy is active in the treatment of patients with paraganglioma.

Parents do matter: genomic imprinting and parental sex effects in neurological disorders

Genomic imprinting is a recently recognized phenomenon of differential expression of genetic material depending upon whether the genetic material has come from the male or female parent. This process of differential phenotypic expression involves mammalian development both in the normal and abnormal situations, resulting in parental sex effects. However, some parental sex effects may be due to other mechanisms such as mitochondrial inheritance. In the following article, evidence for genomic imprinting in experimental animals and in diseases are summarized. Relevant human neurological disorders manifesting parental sex effects discussed here include myotonic dystrophy, Huntington's disease, fragile X syndrome, spinocerebellar ataxia type 1, and neurofibromatosis type 1 and 2. A possible mechanism of imprinting involves the processes of methylation imprint and replication imprint. The knowledge of imprinting is helpful in clinical practice particularly in the areas of genetic counseling, prenatal diagnosis, and possible future gene therapy.

Magnetic resonance imaging or metaiodobenzylguanidine scintigraphy for the demonstration of paragangliomas? Correlations and disparities

Paragangliomas are tumours arising from paraganglionic tissue dispersed from the base of the skull to the pelvic diaphragm. These tumours produce symptoms by secreting catecholamines (functioning tumours) or by local tumour expansion. They can be part of several hereditary disorders. The introduction of magnetic resonance (MR) imaging and metaiodobenzylguanidine (MIBG) scintigraphy has provided new insights into paragangliomas and has tremendously changed the topographic diagnosis of paragangliomas. Both techniques have proven to be adequate in localising paragangliomas. In this report, the performance of these two noninvasive imaging methods in the examination of paragangliomas is compared and the merits and deficits of the two techniques are discussed. Both techniques produce comparable results in the detection of functioning paragangliomas. MR imaging, however, also demonstrates tumours that do not take up MIBG. MR imaging does not involve the use of ionising radiation and is not hampered by medication. Moreover, MR imaging has a higher spatial resolution. Because of these merits it is concluded that for demonstration of paragangliomas, whole-body MR imaging is the preferred and initial method of investigation. MIBG scintigraphy, on the other hand, continues to be a reliable method for non-invasive detection of functioning paragangliomas. At present it is clearly faster in whole-body imaging than MRI and it is definitely patient-friendly (no claustrophobia). It could be reserved for cases where a strong suspicion of a functioning paraganglioma persists, despite normal MR imaging findings, and for cases where doubt exists about the functional activity of one or more multicentric tumours. MIBG scintigraphy must be used in the evaluation of patients referred for iodine-131 MIBG treatment.