Pheochromocytoma

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 tumours, most commonly found at the carotid bifurcation
  • chromaffin tumours arising from aortico-sympathetic 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:

1. Lenders JWM et al. Genetics, diagnosis, management and future directions of research of phaeochromocytoma and paraganglioma: a position statement and consensus of the Working Group on Endocrine Hypertension of the European Society of Hypertension. J Hypertens. 2020 Aug;38(8):1443-1456.