Answer for BIR CoW 01 May 2022
PHEOCHROMOCYTOMA
Findings
Evidence of large T1 hypointense/ T2 heterogenously hyperintense lesion with cystic component noted replacing the left adrenal gland with displacement of pancreas anteriorly. The lesion shows patchy diffusion restriction with low ADC values . On contrast administration , the lesion shows heterogenous enhancement with internal necrosis
Discussion
Pheochromocytomas are rare catecholamine-secreting tumors derived from chromaffin cells. More than 90% of pheochromocytomas are located within the adrenal glands, and 98% occur within the abdomen. Extraadrenal pheochromocytomas develop in paraganglionic chromaffin tissue of the sympathetic nervous system. Common locations for extraadrenal pheochromocytomas include the organ of Zuckerkandl,bladder wall, retroperitoneum, heart, mediastinum, and carotid and glomus jugulare bodies. The most common MR imaging appearance of pheochromocytoma is a mass with low signal intensity at T1-weighted imaging and with high signal intensity at T2-weighted imaging.Pheochromocytomas commonly enhance avidly at T1-weighted imaging after administration of gadolinium-based contrast material.In general, pheochromocytomas appear still more hyperintense on fat-suppressed T2-weighted images due to a signal intensity rescaling effect, which reflects the reduced signal intensity of background fat. The appearance can vary, however, with many low-signal-intensity pheochromocytomas encountered at T2-weighted imaging .In addition, as with CT, pheochromocytomas can also occasionally be wrongly characterized as adenomas on opposed-phase MR images because the diagnosis of adenomas at MR imaging is also dependent on their intracellular fat content. There is indeed considerable overlap between the MR imaging appearance of pheochromocytoma and that of other adrenal lesions. Punctate signal voids representing tumor vessels in paragangliomas create a salt-and-pepper pattern characteristically seen on T1- and T2-weighted images.
REFERENCES:
1.Ros PR, Mortele KJ. CT and MRI of the abdomen and pelvis, a teaching file. Lippincott Williams & Wilkins. (2006) ISBN:0781772370. 2. Kumar V, Abbas AK, Fausto N et-al. Robbins and Cotran pathologic basis of disease. W B Saunders Co. (2005) ISBN:0721601871. 3. Hoegerle S, Nitzsche E, Altehoefer C et-al. Pheochromocytomas: detection with 18F DOPA whole body PET--initial results. Radiology. 2002;222 (2): 507-12. doi:10.1148/radiol.2222010622 . Reiser MF. Magnetic Resonance Tomography. Springer Verlag. (2007) ISBN:354029354X. 5. Pacak K, Eisenhofer G, Lenders JW. Pheochromocytoma, Diagnosis, Localization, and Treatment. Wiley-Blackwell. (2007) ISBN:1405149507.
Findings
Evidence of large T1 hypointense/ T2 heterogenously hyperintense lesion with cystic component noted replacing the left adrenal gland with displacement of pancreas anteriorly. The lesion shows patchy diffusion restriction with low ADC values . On contrast administration , the lesion shows heterogenous enhancement with internal necrosis
Discussion
Pheochromocytomas are rare catecholamine-secreting tumors derived from chromaffin cells. More than 90% of pheochromocytomas are located within the adrenal glands, and 98% occur within the abdomen. Extraadrenal pheochromocytomas develop in paraganglionic chromaffin tissue of the sympathetic nervous system. Common locations for extraadrenal pheochromocytomas include the organ of Zuckerkandl,bladder wall, retroperitoneum, heart, mediastinum, and carotid and glomus jugulare bodies. The most common MR imaging appearance of pheochromocytoma is a mass with low signal intensity at T1-weighted imaging and with high signal intensity at T2-weighted imaging.Pheochromocytomas commonly enhance avidly at T1-weighted imaging after administration of gadolinium-based contrast material.In general, pheochromocytomas appear still more hyperintense on fat-suppressed T2-weighted images due to a signal intensity rescaling effect, which reflects the reduced signal intensity of background fat. The appearance can vary, however, with many low-signal-intensity pheochromocytomas encountered at T2-weighted imaging .In addition, as with CT, pheochromocytomas can also occasionally be wrongly characterized as adenomas on opposed-phase MR images because the diagnosis of adenomas at MR imaging is also dependent on their intracellular fat content. There is indeed considerable overlap between the MR imaging appearance of pheochromocytoma and that of other adrenal lesions. Punctate signal voids representing tumor vessels in paragangliomas create a salt-and-pepper pattern characteristically seen on T1- and T2-weighted images.
REFERENCES:
1.Ros PR, Mortele KJ. CT and MRI of the abdomen and pelvis, a teaching file. Lippincott Williams & Wilkins. (2006) ISBN:0781772370. 2. Kumar V, Abbas AK, Fausto N et-al. Robbins and Cotran pathologic basis of disease. W B Saunders Co. (2005) ISBN:0721601871. 3. Hoegerle S, Nitzsche E, Altehoefer C et-al. Pheochromocytomas: detection with 18F DOPA whole body PET--initial results. Radiology. 2002;222 (2): 507-12. doi:10.1148/radiol.2222010622 . Reiser MF. Magnetic Resonance Tomography. Springer Verlag. (2007) ISBN:354029354X. 5. Pacak K, Eisenhofer G, Lenders JW. Pheochromocytoma, Diagnosis, Localization, and Treatment. Wiley-Blackwell. (2007) ISBN:1405149507.
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!