Endocrine Abstracts

Imaging in paragangliomas can be challenging as they arise from a number of locations including the adrenals, abdomen, pelvic and thoracic sites of chromaffin sympathetic tissue. They can also arise in the head and neck at sites of parasympathetic tissue. They are considered within the group of heterogenous neuroendocrine tumours. In addition to manifesting at multiple sites, they can metastasise, have variable expression of catecholamines and can be a manifestation of hereditary genetic mutations. They are imaged using a variety of functional imaging techniques that target a number of receptors or pathways. Biochemical markers including metanephrines and noradrenalin can be useful. Functional/nuclear imaging include imaging of catecholamine production (MIBG) (usually used as the first line test of choice), somatostatin receptor imaging (octreotide and 68Ga Dotatate) and glucose metabolism (18F-FDG). MR imaging can also be used, particularly in younger patients in order to limit the exposure to radiation. Upto 30% of paragangliomas can be hereditary and can arise either in the adrenals (phaeochromocytomas) or are extra-adrenal in location. Hereditary paragangliomas and sporadic phaeochromocytomas can be the result of germline mutations in succinate dehydrogenase complex subunits B (SDHB) and are also associated with clinical syndromes including Von Hippel Lindau, MEN and NF1. This group of patients can presents with paragangliomas at a young age. Lesions canalso be multiple, bilateral and are often extra-adrenal. This is complicated when (particularly in hereditary cases) patients are asymptomatic or have a neligible elevation of their biochemical markers such as noradrenalin or metanephrines. We discuss the optimal use of multimodality imaging in paragangliomas and phaeochromocytomas including functional imaging, MRI, ultrasound and CT.