Metaiodobenzylguanidine Scan Research Articles

SDHB gene positive metastatic paraganglioma associated with lesions which demonstrate both positive and negative uptake of 18FDG PET and 131MIBG

### Learning Points for Clinicians Paragangliomas are rare caetacholamine secreting neuroendocrine tumours. The diagnosis and management of these tumours is often difficult, particularly as a diagnosis of metastases is often made retrospectively when disease recurrence occurs. In recent years, the role of genotyping has allowed us to better predict which tumours are more likely to be metastatic. Mutations in the SDHB gene have been associated with higher rates of metastatic disease.1 Unfortunately, mutations in this gene can also lower the sensitivity of radiolabeled metaiodobenzylguanidine (MIBG). MIBG scanning is considered the gold standard imaging modality for the diagnosis of recurrent disease but this case illustrates the potential diagnostic pitfalls associated with this imaging modality in cases of SDHB gene mutations. The case demonstrates the importance of genotyping as a diagnostic and predictive tool and the importance of clinical acumen in the face of negative test results. This gentleman underwent a MRI of pelvis in February 2011 for investigation of possible sacroiliitis on a background of known inflammatory bowel disease. This MRI demonstrated a 2.3 × 2.3 cm nodule posterior to the pubic …

Phaeochromocytoma in Nepal – A Single Centre Experience

Phaeochromocytomas are rare tumors of chromaffin cells of neural crest that classically present with symptoms of catecholamine excess such as palpitations, headache and sweating. They are diagnosed by measuring plasma or urinary levels of catecholamines or their metabolites. Anatomic localization is done by computed tomographic scan or magnetic resonance imaging, or meta-iodobenzyl guanidine scan in certain cases. Adequate preoperative catecholamine blockade prevents perioperative hemodynamic instability. To study the clinical spectrum and management of phaeochromocytomas in a tertiary care centre, Tribhuvan University Teaching Hospital, in Nepal. Retrospective review of case records of histologically proven cases of phaeochromocytomas from 2008 -2011 was done, and data collected on clinical spectrum, diagnostic modalities, perioperative management and follow-up. Twelve cases of phaeochromocytomas were operated. The mean age was 36.41+/-14.07 years. There were 2 bilateral phaeochromocytomas and 1 extraadrenal paraganglioma. Apart from the common symptoms of catecholamine excess, patients had atypical presentations like psychiatric manifestations and blurred vision. A combination of urinary Vanillyl Mandelic Acid and computed tomographic scan was used for diagnosis, and open surgery was done in all cases. Pre-operative blood pressure control was achieved by prazocin or calcium channel blockers. Ten patients had intraoperative surge in blood pressure. There were no major morbidity or mortality. Three patients had high blood pressure postoperatively, but were effectively managed with antihypertensives. Phaeochromocytomas can have variable presentation. Good preoperative preparation and perioperative management can result in an excellent outcome.

Functional Mediastinal Pheochromocytoma

A 36-year-old man visited Yeungnam University Hospital with a sudden onset of palpitation, headache, and was found to be hypertensive. Chest radiography showed a 6 cm sized mass lesion on the posterior mediastinum. A biochemical study showed elevated levels of catecholamines. An I-123 metaiodobenzylguanidine scan revealed a hot uptake lesion on the posterior mediastinum. The patient was prepared for surgery with α and β blocking agents. Two months later, we removed the tumor successfully. A histological study proved that the resected tumor was mediastinal pheochromocytoma. Functional mediastinal pheochromocytomas are rare. Therefore, we reported the case with a literature review.

Positive 68 Ga-DOTANOC PET/CT with negative 131 I- metaiodobenzylguanidine scan in a case of Glomus Jugulare

Positive ⁶⁸ Ga-DOTANOC PET/CT with negative ¹³¹ I- metaiodobenzylguanidine scan in a case of Glomus Jugulare

Incidentally discovered intrathoracic extra-adrenal pheochromocytoma during preoperative screening

Introduction: We are reporting a case of an incidental mass later diagnosed as an extradural pheochromocytoma at t2-t4 level during a presurgical work up for a gynecological procedure. Only a few cases of extradural paravertebral tumors are described in literature. case report: this is a clinical case of an asymptomatic 26-year-old female with an incidental finding of thoracic mass in chest X-ray during preoperative screening for myomectomy. Work up for this mass showed elevated plasma and urinary metanephrine levels which was consistent to pheochromocytoma. computed tomography, magnetic resonance imaging and metaiodobenzylguanidine scans demonstrate a mass originating from thoracic spine with cord compression, no adrenal mass, multifocal disease or metastasis. Prior to surgery, the patient was treated with phenoxybenzamine and metoprolol to decrease hemodynamic instability during surgical procedure and also embolization to the arteries supplying the mass to decrease intraoperative bleeding. Patient

Neuroblastoma with a Solitary Intraventricular Brain Metastasis Visualized on I‐123 MIBG Scan

Although metastatic skull lesions of neuroblastoma are not uncommon, brain involvement is infrequent and prompt diagnosis is of utmost importance in such cases. Previous studies have shown that Meta-Iodo-Benzyl-Guanidine (MIBG) scans were not always reliable in detecting central nervous system metastases, however most published reports referred to the Iodine-131 ((131)I)-MIBG scans. Herein, we report an intraventricular metastasis of neuroblastoma diagnosed using an Iodine-123 ((123)I)-MIBG scan, which is increasingly being used in clinical practice and reported as a more accurate method for detecting metastatic lesions. An unusual case of metastatic neuroblastoma to the left lateral ventricle of the brain is presented. Planar (123)I-MIBG scintigraphy showed faint tracer activity close to the midline without asymmetric extensions or abnormal activity in the skull bones. A subsequent brain MR scan revealed an enhancing mass within the left frontal horn consistent with a metastatic lesion. The patient underwent tumor resection with pathology showing neuroblastoma. Our case shows that (123) I-MIBG scintigraphy can be useful in detecting intraventricular brain metastases of neuroblastoma. Although the (123)I-MIBG scintigraphy has been reported to have a significantly superior sensitivity in monitoring asymptomatic patients with neuroblastoma compared with (131)I-MIBG scans, bone marrow histology, bone scan, CT, and urinary catecholamine levels, further studies may be necessary to evaluate its sensitivity in detecting brain lesions.

The Heart of the Matter

b l PRESENTATION In this case, a man with multiple cardiac symptoms suffers cardiac arrest during his medical evaluation, is revived, and is then treated for a very unusual tumor. The patient was a 46-year-old, previously healthy man who presented with complaints of shortness of breath and chest heaviness. Further inquiry revealed generalized fatigue and numerous episodes of profuse sweating over the preceding 2 months. A review of systems was otherwise negative.

Abnormal MIBG uptake in a neuroblastoma patient with right upper lobe atelectasis

A 3-month-old boy with a history of an abdominopelvic neuroblastoma presented 1week after tumor resection for a routine follow-up 123-I Meta-iodobenzylguanidine (MIBG) scan to assess for residual mass. The study demonstrated abnormal radiotracer uptake in the right upper lobe, which correlated on the SPECT/CT to an area of airspace consolidation thought to be secondary to atelectasis. To the best of our knowledge, there is one published case of MIBG radiotracer uptake in the lung correlating with pneumonia; however, there are no reported cases to date in the literature of focal pulmonary MIBG uptake corresponding to atelectasis.

Excessive Blinking and Ataxia in a Child With Occult Neuroblastoma and Voltage-Gated Potassium Channel Antibodies

A previously healthy 9-year-old girl presented with a 10-day history of slowly progressive unsteadiness, slurred speech, and behavior change. On examination there was cerebellar ataxia and dysarthria, excessive blinking, subtle perioral myoclonus, and labile mood. The finding of oligoclonal bands in the cerebrospinal fluid prompted paraneoplastic serological evaluation and search for an occult neural crest tumor. Antineuronal nuclear autoantibody type 1 (anti-Hu) and voltage-gated potassium channel complex antibodies were detected in serum. Metaiodobenzylguanidine scan and computed tomography scan of the abdomen showed a localized abdominal mass in the region of the porta hepatis. A diagnosis of occult neuroblastoma was made. Resection of the stage 1 neuroblastoma and treatment with pulsed corticosteroids resulted in resolution of all symptoms and signs. Excessive blinking has rarely been described with neuroblastoma, and, when it is not an isolated finding, it may be a useful clue to this paraneoplastic syndrome. Although voltage-gated potassium channel complex autoimmunity has not been described previously in the setting of neuroblastoma, it is associated with a spectrum of paraneoplastic neurologic manifestations in adults, including peripheral nerve hyperexcitability disorders.

Retroperitoneal Masses Mimicking Adrenal Tumors

To report 10 cases of neoplasms that were initially thought to be primarily adrenal-derived masses but were later confirmed as tumors of a different origin. Between 2000 and 2011, a total of 229 patients underwent adrenalectomy at our institution. Of this overall group, 10 patients had retroperitoneal pathologic conditions mimicking adrenal tumors. Using an institutional review board-approved database, we reviewed the clinical, biochemical, and radiologic characteristics of these 10 patients. The study cohort consisted of 4 male and 6 female patients. The mean age of these 10 patients was 48 years. The pathologic conditions included schwannoma (n = 3), leiomyosarcoma (n = 2), and 1 each of metastatic angiosarcoma, metastatic granulosa cell tumor, retroperitoneal hematoma, perivascular epithelioid cell tumor, and bronchogenic cyst. The patient with angiosarcoma had elevated plasma and urine catecholamines and a positive metaiodobenzylguanidine scan, whereas the others had normal findings on biochemical work-up. A percutaneous biopsy was performed preoperatively in 2 patients. All patients, except the patient with hematoma, underwent abdominal exploration, which was laparoscopic in 5, open in 2, and robotic in 2. With exclusion of the patients with angiosarcoma and hematoma, resection was possible in all the remaining patients. In this report we describe our experience with retroperitoneal masses mimicking adrenal tumors. Increased awareness of these unusual pathologic conditions is important for appropriate clinical management of these tumors. The presentation of the patients and the surgical management of these individual pathologic entities are highlighted.

Ectopic parathyroid adenoma

Adenoma is the commonest cause of primary hyperparathyroidism; 10% of these adenomas can be ectopic, leading to one of the major causes for persistent and recurrent hyperparathyroidism. Proper preoperative evaluation is important in order to localize the position of the glands. We report a case of a 21-year-old male who presented with features of primary hyperparathyroidism. On evaluation with metaiodobenzylguanidine scan, he was found to have a parathyroid adenoma in the mediastinum, anterior to the arch of the aorta. The adenoma was excised via a sternotomy incision.

Congruence of Ga-68 Dotanoc positron emission tomography-computed tomography and metaiodobenzylguanidine scan in a patient of metastatic medullary thyroid carcinoma

Congruence of Ga-68 Dotanoc positron emission tomography-computed tomography and metaiodobenzylguanidine scan in a patient of metastatic medullary thyroid carcinoma

Congenital Agenesis of Right Parotid Gland Confounds MIBG Scan Interpretation in Craniocervical Neuroblastoma

A 10-month-old boy with left infraorbital temporal neuroblastoma presented for I-123 metaiodobenzylguanidine scan with SPECT/CT for staging. Symmetrical metaiodobenzylguanidine uptake in salivary glands is usually considered normal. In this case of right parotid agenesis, symmetrical uptake was misleading. Tumor in the right mandibular ramus masqueraded as normal parotid gland. Repeat imaging 3 months after chemotherapy revealed absence of physiologic right parotid gland activity. Correlation with CT from SPECT/CT demonstrated right parotid agenesis, confirmed on MRI. Few cases of unilateral parotid agenesis are reported in published literature. We also discuss the potential added value of higher-quality CT images in SPECT/CT tumor imaging.

Case Scenario: Metastatic Pediatric Paraganglioma Presenting during the Course of an Elective Surgery

P HEOCHROMOCYTOMA and paraganglioma are neuroendocrine tumors rarely diagnosed in pediatric patients. The incidence of malignant pheochromocytoma and paraganglioma in childhood is approximately 0.02 cases per million every year. Coincidental intraoperative diagnosis of pheochromocytoma involves very high mortality rates, reaching 50%. We present a case of coincidental diagnosis of pediatric metastatic malignant paraganglioma during an elective surgical procedure. The evaluation and management of pheochromocytoma and paraganglioma are discussed.

Pheochromocytoma presenting with arterial and intracardiac thrombus in a 47-year-old woman: a case report

IntroductionPheochromocytoma is a rare cause of hypertension but it could have severe consequences if not recognized and treated appropriately. The association of pheochromocytoma and thrombosis is even rarer but significantly increases management complexity, morbidity and mortality. To the best of our knowledge, this is the first report of a patient with pheochromocytoma presenting with left axillary arterial and intracardiac thrombus.Case presentationA 47-year-old Caucasian woman with a past medical history of hypertension presented for medical attention with left arm numbness. Doppler ultrasound showed an obstructing thrombus in her left axillary artery. She had symptom resolution after stent placement in her left axillary artery. A subsequent echocardiogram demonstrated a large intracardiac mass and abdominal computed tomography revealed a 7 cm mass between her spleen and left kidney. Labile blood pressure was noted during admission and she had very high levels of plasma and 24-hour urine catecholamines and metanephrines tests. A (123)I- metaiodobenzylguanidine scan showed intense uptake in the left abdominal mass. After adequate alpha blockage with phenoxybenzamine, laparoscopic tumor resection was performed without complications. She had normal metanephrines and complete symptom resolution afterwards. The intracardiac mass also disappeared with anticoagulation. All other endocrine laboratory abnormalities returned to normal after surgery.ConclusionArterial and ventricular thrombosis occurring in patients with pheochromocytoma is rare. A multi-disciplinary approach is necessary in caring for this type of patient. Catecholamines likely contributed to the development of thrombosis in our patient. Early recognition of pheochromocytoma is the key to improving outcome.

Evaluation of morphological/immunohistochemical versus nuclear medicine imaging modalities in detecting metastatic bone and/or marrow deposits in neuroblastoma patients

Background & PurposeIn planning diagnostic or follow-up investigational strategies, neuroblastoma (NB) metastatic deposits in bone and/or bone marrow (BM) should be detected as early as possible. Therefore, all investigational detection tools should be conducted simultaneously for precise staging. However, because of the financial conditions in our developing countries and in view of the cost/benefit relationship, the question is, can one detection tool only become satisfactory and replacing others? The purpose of our study is to compare simultaneous results of bone and metaiodobenzylguanidine (MIBG) scans versus BM biopsies with immunohistochemical (IHC) staining; in detecting bone and/or BM metastatic deposits in NB patients. Material and methodsThis study included 138 NB patients; 46 were de novo and 92 were under follow-up. They were subjected to bilateral BM biopsies, IHC staining (using NSE McAb) and Tc-99m methylene diphosphonate (Tc-99m MDP) bone scan (BS). Only 57/138 patients were, in addition, subjected to I-131 MIBG scan. ResultsMatched results between IHC-stained BM sections and bone scans (BSs) 107/138 (77.5%) were higher than the un-matched ones 31/138 (22.5%). There was a moderate agreement between the two methods in all studied cases (Kappa=0.538) and it was higher among de novo (Kappa=0.603) than follow-up group (Kappa=0.511). Among the 31 un-matched results, the most frequent (17/31) were due to the presence of minute amount of infiltrating NB cells that could be detected by IHC-stained BM sections and not by BSs. The less frequent (12/31) were due to the presence of metastatic deposits outside pelvic bones that could be detected by BSs and not by IHC-stained BM sections mainly in the follow-up cases (11/12) rather than de novo cases (1/12). The matched results between IHC-stained BM sections and MIBG scans 54/57 (94.7%) were higher than the un-matched ones 3/57 (5.3%). The agreement between the two methods was higher among de novo (Kappa=1.000) than follow-up group (Kappa=0.847). The agreement between IHC-stained BM sections and MIBG scans was substantial (Kappa=0.890) while that between IHC-stained BM sections and BSs was moderate (Kappa=0.538). ConclusionsWe suggest a step-wise strategy to be applied, at least in developing countries, in approaching de novo and follow-up NB cases for detecting bone and/or BM metastatic deposits. This strategy might be beneficial if it is considered during application of NB guide-lines for diagnosis and follow-up.

An Unusual Case of Gastrointestinal Bleeding

A 10-year-old boy presented with a 3-day history of worsening abdominal pain, fever, emesis and melena. Abdominal ultrasound revealed a right upper quadrant mass that was confirmed by computed tomography angiogram (CTA), which showed an 8 cm well-defined retroperitoneal vascular mass. 123Iodine metaiodobenzylguanidine (123MIBG) scan indicated uptake only in the abdominal mass. Subsequent biopsy revealed a paraganglioma that was treated with chemotherapy. This case represents an unusual presentation of a paraganglioma associated with gastrointestinal (GI) bleeding and highlights the utility of CTA and 123MIBG in evaluation and treatment.

Phase II Study of Irinotecan and Temozolomide in Children With Relapsed or Refractory Neuroblastoma: A Children's Oncology Group Study

This phase II study was conducted to determine the response rate associated with use of irinotecan and temozolomide for children with relapsed/refractory neuroblastoma. Patients with relapsed/refractory neuroblastoma measurable by cross-sectional imaging (stratum 1) or assessable by bone marrow aspirate/biopsy or metaiodobenzylguanidine (MIBG) scan (stratum 2) received irinotecan (10 mg/m(2)/dose 5 days a week for 2 weeks) and temozolomide (100 mg/m(2)/dose for 5 days) every 3 weeks. Response was assessed after three and six courses using International Neuroblastoma Response Criteria. Of the first 25 evaluable patients on a given stratum, five or more patients with complete or partial responses were required to conclude that further study would be merited. Fifty-five eligible patients were enrolled. The objective response rate was 15%. Fourteen patients (50%) on stratum 1 and 15 patients (56%) on stratum 2 had stable disease. Objective responses were observed in three of the first 25 evaluable patients on stratum 1 and five of the first 25 evaluable patients on stratum 2. Less than 6% of patients experienced ≥ grade 3 diarrhea. Although neutropenia was observed, less than 10% of patients developed evidence of infection while neutropenic. The combination of irinotecan and temozolomide was well tolerated. The objective response rate of 19% in stratum 2 suggests that this combination may be effective for patients with neuroblastoma detectable by MIBG or marrow analysis. Although fewer objective responses were observed in patients with disease measurable by computed tomography/magnetic resonance imaging, patients in both strata seem to have derived clinical benefit from this therapy.

Malignant Pheochromocytoma Metastasis to the Breast Shown on I-123 MIBG Scan

A 36-year-old woman was referred to our department for I-123 metaiodobenzylguanidine (MIBG)-SPECT/CT scan 3 years after surgical excision of pheochromocytoma. She was referred due to recurrence of her symptoms as well as raised urinary catecholamines. Review of I-123 MIBG scan revealed multiple MIBG-avid metastatic lesions. Most of these were bony lesions, however, there were also 2 soft tissue lesions in the left breast. She subsequently underwent ultrasound-guided fine-needle aspiration of the left breast lesions. Fine-needle aspiration revealed cytologic changes consistent with pheochromocytoma. There has only been 1 previous reported case of pheochromocytoma metastasizing to the breast. This is the first case in which the metastasis was detected by I-123 MIBG scan.

Sequential imaging analysis using MIBG scintigraphy revealed progressive degeneration of cardiac sympathetic nerve in Parkinson’s disease

Metaiodobenzylguanidine (MIBG) cardiac scintigraphy was used to differentiate Parkinson's disease (PD) with Lewy body pathology from other degenerative parkinsonisms. MIBG cardiac scintigraphy demonstrates the extent of degeneration of myocardial post-ganglionic sympathetic nerves in patients with PD. Because of its specificity for Lewy body (LB) pathology, MIBG scan might also be useful biomarker for the neurodegeneration attributed to PD. To estimate the utility of the imaging technique as a biomarker, we conducted sequential imaging analysis and power analysis. Sixty-three patients who met the UK PD Society Brain Bank criteria were enrolled in this study. (123) I-MIBG myocardial scintigraphy was performed on all subjects, and the heart to mediastinum (H/M) ratio was calculated. A second imaging session was carried out after a mean interval of 268 days. Sequential imaging revealed a 2.9% decline of the H/M ratio from the baseline to the follow-up image, which reached statistical significance, but the power analysis showed that a relatively large number of patients would be required to demonstrate the neuroprotective effects of any therapy. Sequential imaging using (123) I-MIBG myocardial scintigraphy revealed progressive degeneration of the cardiac sympathetic nerve in 63 patients with PD. Although careful elimination of other disease conditions that damage the cardiac sympathetic nerve system is necessary, (123) I-MIBG myocardial scintigraphy may be a useful addition to clinical trials that intend to prove neuroprotection among patients with PD.