Paragangliomas (PGLs) are neuroendocrine tumors arising from the neural crest and localized from the skull base to the pelvic floor. In particular, parasympathetic PGLs arise in the head/neck region (carotid body, vagal nerve, jugulare and tympanic glomus) and more rarely in the anterior thorax, while sympathetic PGLs are localized in the posterior thorax and in the abdomen and secrete catecholamines.
Localization of paragangliomas might be performed by anatomical (CT and MRI) and functional (nuclear medicine) imaging studies. The latter are useful to confirm the diagnosis, when CT/MRI are negative in spite of positive biochemical data or to detect multifocal or metastatic disease.
In this study we evaluated 15 patients affected by PGL-1, an hereditary syndrome caused by SDHD gene mutations and characterized by multiple PGLs and/or pheochromocytomas.
CT and MRI detected 27 PGLs: 11 glomus tumors, 6 vagal PGLs, 3 jugular PGLs, 1 tympanic PGL, 3 thoracic PGLs and 3 abdominal PGLs. All patients underwent scintigraphy with 111In-pentetreotide (octreoscan), while scintigraphy with 123I-metaiodobenylguanidine (MIBG) was performed in 8 patients. Octreoscan identified the majority of head/neck PGLs (18/21) and all thoracic PGLs, but it was negative in all abdominal PGLs; on the contrary MIBG resulted positive in each abdominal PGLs, in 2/3 thoracic PGLs and only in 1/12 PGLs in the head-neck region.
In conclusion, PGLs show a differential tracer uptake confirming their different nature: PGLs wich are parasympathetic in origin are detected by Octreoscan, while PGLs wich are sympathetic in origin are preferentially detected by MIBG.
The presence of a high concentration of somatostatin receptors in parasympathetic PGLs suggests to further evaluate their functional role in these tumors in the hope that somatostatin analogues might represent an alternative treatment to surgery in patients whose tumors cannot be surgically removed because of their dimensions or location.
01 - 05 Apr 2006
European Society of Endocrinology