Clinical relevance of phenotype/genotype correlations in the diagnosis and therapy of pheochromocytomas/paragangliomas.

Pheochromocytomas and paragangliomas are tumors arising from neural crest-derived cells. They can be sympathetic in origin, catecholamine secreting and located in the abdomen or chest, or parasympathetic, generally non-secreting and located in the head and neck region. It is well established that about 35\% of them are genetically determined. Germ-line mutations in one of the 10 so far known susceptibility genes is especially suspected when the tumors are diagnosed in young patients, multiple or recurrent or associated with additional lesions typical of syndromic clinical pictures such as von Hippel-Lindau, Multiple Endocrine Neoplasia type 2 or Neurofibromatosis type 1. Tumor genetic profile determines the type and pattern of catecholamine release, the clinical presentation, the risk of malignancy and may influence the choice of the radiotracers used in functional imaging, the type of surgical procedures as well as the type of medical therapy in the treatment of metastatic disease.