<prompt> False statement about extra adrenal pheochromocytoma -Constitute 50 of totalMay occur in BladderMay occur in thoraxInvolve carotid body  <response>: Extra-adrenal pheochromocytomas may arise in any poion of the paraganglion system, although they most commonly occur below the diaphragm. The most common site of occurrence of extra-adrenal pheochromocytoma is the superior para-aoic region between the diaphragm and lower renal poles. Although the traditional teaching has been that 10 of all pheochromocytomas are at extra-adrenal sites, this may be an underestimation. Extra-adrenal pheochromocytomas probably represent at least 15 of adult and 30 of childhood pheochromocytomas. They may be malignant in up to 40 of the cases, although conflicting data add to the unceainty of this point. Patients with tumors arising at extra-adrenal sites commonly present with headache, palpitations, sweating and hypeension. The diagnosis is most often confirmed by demonstrating increased catecholamine production, usually by measurement of urinary catecholamines andor their metabolites. Ref - Harrison 17 pg 2269 , pubmed.com , 