False statement about extraadrenal pheochro mocytoma: (PGI May 2010)
Ans : A (Constitute..) Pheochromocytoma arise from: Harrison 17th/2270Adrenal MedullaQExtraadrenalRetroperitonealQPelvicQThoracicfi.e., mediastinum) Q"The 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"- CMDT09/1031'Though 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 7th/1084"The carotid body tumor is a typical paraganglioma, forming a palpable mass in the neckQ"- Robbins 7tb/1221'When extraadrenal, pheochromocytomas are also called paragangliomas"- Sabiston 18th/998"Extraadrenal: Abdominal or thoracic - Sabiston 18th/1021"The 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 7th/2262231-MSBG is essential for the detection of multiple extra-adrenai tumors: & metastasis"- BL 25th/813'T2-weighted MRl with gadolinium contrast is optimal for detecting pheochromocytomas and is somewhat better than CT: for imaging extraadrenal pheochromocytomas and paragangliomas"- Harrison 17th/2271"Extra-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 18th/2373Morphological & 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-100*Pheochromocytoma : Review of factsIt is catecholamine'-' producing tumour of sympathetic or Parasympathetic nervous systemPheochromocytomas usually subscribe to aconvenient "rule of 10" (Robbins, Harrison & CMDT)10% are bilateral;10% are malignant'''10% are extra adrenal*10% are associated with familial syndrome*10% arise in childhoodApproximately 10% are in thoraxMost are < 10 cm in diameter*'10% 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.
Constitute 50% of total pheochromocytoma
May occur in Bladder
May occur in thorax
involve carotid body
Kidney