<prompt> False statement about extraadrenal pheochro mocytoma: PGI May 2010Constitute 50 of total pheochromocytomaMay occur in BladderMay occur in thoraxinvolve carotid body  <response>: Ans : A Constitute.. Pheochromocytoma arise from: Harrison 17th2270Adrenal MedullaQExtraadrenalRetroperitonealQPelvicQThoracicfi.e., mediastinum QThe tumor is located in either or both adrenals or anywhere along the sympathetic nervous chain, and rarely in such aberrant locations as the thorax, bladder, or brain- CMDT091031Though usually found in the adrenal medulla, these vascular tumors can occur anywhere, such as in the right atrium, the spleen, the broad ligament of the ovary, or the organs of Zuckerkandi at the bifurcation of the aorta or carotid bodyQ- Miller Anesthesia 7th1084The carotid body tumor is a typical paraganglioma, forming a palpable mass in the neckQ- Robbins 7tb1221When extraadrenal, pheochromocytomas are also called paragangliomas- Sabiston 18th998Extraadrenal: Abdominal or thoracic - Sabiston 18th1021The sensitivity of M1BG scanning with 1131 for pheochromocytoma is 100 and specificity 95-98 making it the most useful investigation for the localization of pheochromocytoma, including those that arise at nonadrenal sites- Devita 7th2262231-MSBG is essential for the detection of multiple extra-adrenai tumors: metastasis- BL 25th813T2-weighted MRl with gadolinium contrast is optimal for detecting pheochromocytomas and is somewhat better than CT: for imaging extraadrenal pheochromocytomas and paragangliomas- Harrison 17th2271Extra-adrenal tumor may be difficult to detect by USG.CT or MRL MIBG is taken by chromaffin tissue anywhere in the body is useful for localizing small tumors- Nelson 18th2373Morphological Microscopic Features of Pheochro- mocvtoma On section, the cut surfaces of smaller pheochromocytomas are yeliowtan. Larger lesions tend to be haemorrhagic, necrotic cystic.The tumour is composed of polygonal to spindle shaped chromaffin cells or chief cells, clustered with sustentacular cells into small nests or alveoli zeiibaUen f by a rich vascular network. The nuclei are usually round to avoid, with a stippled salt pepper chromatin that is characteristic of most neuroendocrine tumours.Immunoreactivity for neuroendocrine markers chromogranin synaptophysinf is present in chief cells while the peripheral sustentacular cells label with S-100Pheochromocytoma : Review of factsIt is catecholamine- producing tumour of sympathetic or Parasympathetic nervous systemPheochromocytomas usually subscribe to aconvenient rule of 10 Robbins, Harrison CMDT10 are bilateral;10 are malignant10 are extra adrenal10 are associated with familial syndrome10 arise in childhoodApproximately 10 are in thoraxMost are 10 cm in diameter10 not associated with HypertensionAbout 10 tumour involves both adrenal gland10 extradrenal tumour are extra abdominalThe clinical presentation is so variable that pheochromocytoma has been termed the great masquerader.Among the presenting symptoms, episodes of palpitation, headache profuse sweating are typical constitute a classic triad. The classic triad in association with hypertension makes pheochromocytoma a likely diagnosis.The mean age at diagnosis is about 40 years, although the tumours can occur from early childhood until later in life.Hypertension is most common manifestationSolitary lesion inexplicably favour right sideDiagnosis is based on documentation of catecholamines excess by biochemical testing localisation of the tumour by imagingT2, weighted MRI with gadolinium contrastQ is optimal for detecting pheochromocytoma is somewhat better than CT for imaging extradrenal pheochromocytoma. Due to lack of radiation, MRl scanning is investigation of choice during pregnancy childhood. However Both CT MRl scanning have a sensitivity of about 90 for adrenal pheochromocytoma. 