Phaeochromocytomas are functional tumours that arise from chromaffin cells in the adrenal medulla.
- incidence among the general population is about 0.8 per 100,000 person-years, and is estimated to be 0.1-0.6% in the hypertensive population
- diagnosis usually takes place in patients aged 40-50 years
- however, hereditary variants, such as multiple endocrine neoplasia type 2, Von Hippel-Lindau disease, neurofibromatosis type 1 and the pheochromocytoma-paraganglioma syndrome, can present earlier
Phaeochromocytomas usually secrete a combination of noradrenaline and adrenaline, but some tumours may also secrete dopamine and rarely ACTH causing Cushing's syndrome.
- rare tumours of (APUD cells)
- chromaffin cells of the adrenal medulla
- paraganglion cells of the sympathetic nervous system
- APUD cells : embryologically derived from the neuroectoderm
- functionally involved in amine and amine precursor uptake and decarboxylation :APUD
- occur in a variety of non endocrine (intestines, lungs) and endocrine (adrenals, thyroid, parathyroid) tissues
- paragangliomas (Extra-adrenal phaeochromocytomas), also called the vascular head and neck tumors, most commonly found at the carotid bifurcation
- chromaffin tumours arising from aorticosympathetic paraganglia have histologic, biochemical and clinical similarities to phaeochromocytomas and are sometimes referred to as extra-adrenal phaeochromocytomas
May be discovered as an adrenal "incidentaloma"( 5% are pheochromocytomas).
Several genetic syndromes, all of which are transmitted in an autosomal dominant fashion, are known to be associated with an increased risk for pheochromocytoma, including von Hippel-Lindau (VHL) syndrome, multiple endocrine neoplasia type 2 (MEN 2), which is associated with mutations in the RET proto-oncogene, and neurofibromatosis type 1 (NF1)
Reference:
- Harmut PH et al. Pheochromocytomas, multiple endocrine neoplasia type 2, and von Hippel-Lindau disease. NEJM 1993;329 (21): 1531-8.
- Lenders JW, Eisenhofer G, Mannelli M, Pacak K. Phaeochromocytoma. Lancet. 2005;20-26;665-75.
- Guerrero MA, Schreinemakers JM, Vriens MR, et al. Clinical spectrum of pheochromocytoma. J Am Coll Surg. 2009;209:727-32.
- Bryant J, Farmer J, Kessler LJ, Townsend RR, Nathanson KL. Pheochromocytoma: the expanding genetic differential diagnosis. J Natl Cancer Inst. 2003 Aug 20;95(16):1196-204