MIBG Case 4 Answers
1) Any abnormal uptake?
Two areas of abnormal uptake are noted. One lies in the midline in the low abdomen, the other is a faint region to the left of the mid-mediastinum. On CT the mediastinal lesion had been overlooked initially and the midline abdominal lesion was arising de novo in the organ of Zuckerkandl.2) Is this a recognized syndrome?
Yes, familial phaeochromocytomas and paragangliomas is a recognized very rare syndrome. Isolated familial phaeochromocytoma is genetically very similar to von-Hippel Lindau syndrome and thought to be a poorly penetrate variant of this. Phaeochromocytomas are also associated with Neurofibromatosis type 1, MEN 2, von Hippel-Lindau syndrome and Carney's syndrome.3) What percentage of phaeochromocytomas are extra-adrenal in adults?
Phaeos obey the rule of 10s. 10% are extraadrenal, 10% are malignant, 10% occur in the paediatric population, 10% are multiple, 10% are familial and 10% are cystic.The larger the tumour, the more malignant it tends to be. Children tend to have multiple, extra-adrenal tumours that are more malignant. Extra-adrenal tumours generally arise in the retroperitoneal sympathetic chain or near the organ of Zuckerkandl (caudal to the original of the IMA). Mediastinal phaeos make up ~1% of all phaeos. In adults, extra-adrenal lesions are malignant in 30-40% of cases whereas this is not true in children.
The text is entirely the opinion of the author and does not necessarily reflect that of RUH NHS Trust or the Bristol Radiology Training Scheme. Website content devised by Paul McCoubrie.