Detection Of Paragangliomas Research Articles

7958 Organ Of Zuckerkandl Paragangliomas

Abstract Disclosure: L. McVicker: None. S. Egan: None. K.C. Conlon: None. J. Gibney: None. J. Feeney: None. M. Whelan: None. A. Garrahy: None. Background: The Organ of Zuckerkandl (OoZ) was first described in 1901 by an Austrian anatomist Emile Zuckerkandl as a para-aortic paraganglia located laterally to the abdominal aorta at the level of the inferior mesenteric artery. It represents the largest accumulation of extra-adrenal chromaffin cells in mammals. Paragangliomas (PGL) of the OoZ are rare entities with prior retrospective study of 371 patients with phaeochromocytoma or sympathetic PGL revealing only 21 cases of OoZ PGLs of which 14 of which (66%) had metastases at diagnosis (1). 70% of cases are in association with SDHB or less commonly, SDHD mutations (2). Clinical Case: A 48-year-old female presented with a year long history of palpitations and headache. Plasma normetanephrine level was 6340 pmol/L (lab reference 0-1180), plasma metanephrine 412 pmol/L (lab reference 0-510) and plasma 3-methoxytyramine <100 pmol/L (lab reference 0-180). CT adrenals showed normal adrenal glands. A 4.5 cm x 2.1 cm hyper-vascular retroperitoneal mass was visualised. A 68Ga-DOTATOC PET/CT showed no abnormal uptake in the area of the mass. [1]23I-MIBG scan showed increased uptake within the mass compatible with a PGL of the OoZ. Following surgery, histology confirmed PGL of the OoZ and plasma metanephrines normalised following. Genetic testing for predisposing mutation was negative. A 38-year-old male presented with sweating episodes, palpitations, and hypertension. Plasma normetanephrine level was 2,230 pmol/L (lab reference 0-1180) and plasma metanephrines 223 pmol/L (lab reference 0-520). CT adrenals showed normal adrenal glands with no other abnormalities noted. [1]23I-MIBG showed increased uptake in the region of the origin of the inferior mesenteric artery from the aorta consistent with PGL of the OoZ. The patient underwent laparoscopic resection with resultant normalisation of metanephrine levels. Histology showed a 21 mm encapsulated tumour in keeping with PGL with a PASS Score of 7. As with the first case, genetic testing for predisposing mutations returned negative. Conclusion: OoZ PGLs represent rare presentations of phaeochromocytoma-paraganglioma disease. This small case series is notable as neither case was associated with a predisposing genetic mutation, which has previously been shown to be more common in OoZ PGLs. There was also no evidence of metastasis in either case which is more commonly associated with this OoZ disease. The first case is also remarkable in terms of the tumour’s imaging characteristics. Previous studies have shown greater sensitivity using 68Ga-DOTA-Somatostatin Analogue PET/CT in comparison to [1]23I-MIBG in the detection of PGLs (3). In the first case, the tumour did not show any significant avidity on 68Ga-DOTATOC PET/CT but was avid on [1]23I-MIBG. Reference: 1. Ayala-Ramirez et al. J Clin Endocrinol Metab. 2011 2. Lodish et al. Endocr Relat Cancer. 2010 3. Carrasquillo et al. J Nuclear Medicine. 2021 Presentation: 6/2/2024

Current status of functional imaging in neuroblastoma, pheochromocytoma, and paraganglioma disease.

Diagnostic imaging plays an important role in the detection of paraganglioma (PGL), pheochromocytoma (PCC), and neuroblastoma (NB). Anatomic imaging, for example CT or MRI, offers high sensitivity in these neuroendocrine tumors (NET) but only moderate specificity, often associated with difficulties in clearly distinguishing between NET and non-NET. Functional imaging, as in the use of different radioisotopes, is indispensable in oncological imaging. The introduction of PET and PET/CT, respectively, led to adramatic improvement in both malignant and non-malignant PGL, PCC, and NB, assessing the exact tumor extent. This review gives an overview of functional and anatomical imaging in PGL, PCC, and NB.

Early Detection of Paragangliomas in SDHD and SDHB Mutation Carriers

Early Detection of Paragangliomas in SDHD and SDHB Mutation Carriers

The Effects of Carbidopa on Uptake of 6-18F-Fluoro-L-DOPA in PET of Pheochromocytoma and Extraadrenal Abdominal Paraganglioma

6-(18)F-fluoro-l-3,4-dihydroxyphenylalanine ((18)F-DOPA) PET is a useful tool for the detection of certain neuroendocrine tumors, especially with the preadministration of carbidopa, an inhibitor of DOPA decarboxylase. Whether carbidopa also improves (18)F-DOPA PET of adrenal pheochromocytomas and extraadrenal paragangliomas is unknown. The aim of this study was to investigate the sensitivity of (18)F-DOPA PET in the detection of paraganglioma and its metastatic lesions and to evaluate whether tracer uptake by the tumors is enhanced by carbidopa. Two patients with nonmetastatic adrenal pheochromocytoma, and 9 patients with extraadrenal abdominal paraganglioma (1 nonmetastatic, 8 metastatic), underwent whole-body CT, MRI, baseline (18)F-DOPA PET, and (18)F-DOPA PET with oral preadministration of 200 mg of carbidopa. The dynamics of tracer uptake by these lesions and the physiologic distribution of (18)F-DOPA in normal tissues were recorded. Seventy-eight lesions were detected by CT or MRI, 54 by baseline (18)F-DOPA PET (P = 0.0022 vs. CT/MRI), and 57 by (18)F-DOPA PET plus carbidopa (P = 0.0075 vs. CT/MRI, not statistically significant vs. baseline). In reference to findings on CT and MRI, the sensitivities of baseline (18)F-DOPA PET were 47.4% for lesions and 55.6% for positive body regions, versus 50.0% (lesions) and 66.7% (regions) for (18)F-DOPA PET plus carbidopa (neither is statistically significant vs. baseline). Compared with baseline, carbidopa detected additional lesions in 3 (27%) of 11 patients. Carbidopa increased the mean (+/-SD) peak standardized uptake value in index tumor lesions from 6.4 +/- 3.9 to 9.1 +/- 5.6 (P = 0.037). Pancreatic physiologic (18)F-DOPA uptake, which may mask adrenal pheochromocytoma, is blocked by carbidopa. Carbidopa enhances the sensitivity of (18)F-DOPA PET for adrenal pheochromocytomas and extraadrenal abdominal paragangliomas by increasing the tumor-to-background ratio of tracer uptake. The sensitivity of (18)F-DOPA PET for metastases of paraganglioma appears to be limited.

Utility of thallium-201 and iodine-123 metaiodobenzylguanidine in the scintigraphic detection of neuroendocrine neoplasia.

Metaiodobenzylguanidine (MIBG) is a specific marker for neuroendocrine tumours, such as phaeochromocytoma, neuroblastoma, medullary thyroid cancer (MTC) and paraganglioma, but it suffers in some cases (especially in MTC) from a lack of sensitivity. Thallium is a well-known marker of cellularity with a great sensitivity and a lack of specificity. In order to determine whether the association of these two markers is able to improve the detection of neuroendocrine lesions, 137 scintigraphic examinations using MIBG and thallium were performed in 101 patients referred for suspicion or follow-up of neuroendocrine tumours. Thallium chloride was first injected (1 MBq/kg), images being acquired about 20 min after injection; 123I-MIBG (4 MBq/kg) was then injected and images acquired 5 and 24 h later. In patients with phaeochromocytoma or neuroblastoma, thallium scintigraphy appeared of little help since no tumoural site was discovered by thallium accumulation alone. In contrast, thallium examination seemed of interest in the detection of paraganglioma and MTC, the association of the two radiopharmaceuticals increasing the number of detected sites.