Answer for BIR CoW 29 Dec 2024
PHEOCHROMOCYTOMA
Findings
Well defined T1 heterogeneously isointense relatively T2 hyperintense lesion noted arising from left supra-adrenal fossa showing diffusion restriction and showing no signal drop in out of phase imaging. On contrast administration, the lesion shows heterogenous enhancement. The lesion measures 4 (anteroposterior) x 5.5 (transverse) x 7.5 (craniocaudal) cm The lesion is noted indenting anterosuperior aspect of left kidney with no infiltration, with displacement of distal body and tail of pancreas anteriorly.
Discussion
Pheochromocytomas are catecholamine-producing tumors which arise from ganglion cells anywhere in the autonomic nervous systern. About 90% of pheochromocytomas originate in the adrenal medulla while 10% are extra-adrenal, the common sites being paravertebral sympathetic ganglia, organ of Zuckerkandi, urinary bladder, neck, or mediastinum. About 10% of pheochromocytomas are bilateral and 10% are malignant. About 5-10% are inherited as autosomal dominant either alone or in combination with other abnormalities such as multiple endocrine neoplasia (Type I or III), neurofibromatosis, von Hippel-Lindau's retinal, and cerebellar hemangioblastomas. Clinical features: Hypertension, paroxysmal attacks of palpitations, headache, sweating, and biochemical tests of plasma catecholamine levels and 24-hour urine vanillylmandelic acid level can provide the diagnosis. Imaging: USG: Pheochromocytoma is seen as well-defined hypoechoic mass, which may show areas of necrosis or hemorrhage. CT: It is the technique of choice to confirm adrenal mass. It is seen as soft-tissue density mass with intense contrast enhancement on CECT. MRI: it is isointense or hypointense on T1WI and extremely hyperintense on T2WI. Although this finding is almost universally seen with pheochromocytomas, a percentage of adrenal metastases has overlapping findings. In addition, a significant number of lesions may not show this typical T2 hyperintensity. Gadolinium-DTPA (diethylenetriamine penta-acetic acid) produces marked enhancement with slower washout of contrast as compared to adenoma. Pheochromocytomas show insignificant signal drop on out-of-phase GRE images. Only the presence of metastases can clearly define a pheochromocytoma as malignant. CT and MRI can detect adrenal pheochromocytoma equally well. However, MRI is better for detecting extra-adrenal pheochromocytoma and recurrence after surgery. nuclear scan: In patients with strongly suspected pheochromocytoma, but no adrenal mass identified on CT or MRI, MIBG scintigraphy is the technique of choice to detect ectopic location and is also indicated for metastatic or locally recurrent disease. It is seen as focal area of abnormal activity. The sensitivity of MIBG scintigraphy for detecting pheochromocytoma is 80-90% with a specificity of 90-100%, but a positive MIBG scintigraphy should always be correlated with CT or MRI.
Reference:
Aiims-Mamc-Pgi'S Comprehensive Textbook of Diagnostic Radiology (3Vols)
Findings
Well defined T1 heterogeneously isointense relatively T2 hyperintense lesion noted arising from left supra-adrenal fossa showing diffusion restriction and showing no signal drop in out of phase imaging. On contrast administration, the lesion shows heterogenous enhancement. The lesion measures 4 (anteroposterior) x 5.5 (transverse) x 7.5 (craniocaudal) cm The lesion is noted indenting anterosuperior aspect of left kidney with no infiltration, with displacement of distal body and tail of pancreas anteriorly.
Discussion
Pheochromocytomas are catecholamine-producing tumors which arise from ganglion cells anywhere in the autonomic nervous systern. About 90% of pheochromocytomas originate in the adrenal medulla while 10% are extra-adrenal, the common sites being paravertebral sympathetic ganglia, organ of Zuckerkandi, urinary bladder, neck, or mediastinum. About 10% of pheochromocytomas are bilateral and 10% are malignant. About 5-10% are inherited as autosomal dominant either alone or in combination with other abnormalities such as multiple endocrine neoplasia (Type I or III), neurofibromatosis, von Hippel-Lindau's retinal, and cerebellar hemangioblastomas. Clinical features: Hypertension, paroxysmal attacks of palpitations, headache, sweating, and biochemical tests of plasma catecholamine levels and 24-hour urine vanillylmandelic acid level can provide the diagnosis. Imaging: USG: Pheochromocytoma is seen as well-defined hypoechoic mass, which may show areas of necrosis or hemorrhage. CT: It is the technique of choice to confirm adrenal mass. It is seen as soft-tissue density mass with intense contrast enhancement on CECT. MRI: it is isointense or hypointense on T1WI and extremely hyperintense on T2WI. Although this finding is almost universally seen with pheochromocytomas, a percentage of adrenal metastases has overlapping findings. In addition, a significant number of lesions may not show this typical T2 hyperintensity. Gadolinium-DTPA (diethylenetriamine penta-acetic acid) produces marked enhancement with slower washout of contrast as compared to adenoma. Pheochromocytomas show insignificant signal drop on out-of-phase GRE images. Only the presence of metastases can clearly define a pheochromocytoma as malignant. CT and MRI can detect adrenal pheochromocytoma equally well. However, MRI is better for detecting extra-adrenal pheochromocytoma and recurrence after surgery. nuclear scan: In patients with strongly suspected pheochromocytoma, but no adrenal mass identified on CT or MRI, MIBG scintigraphy is the technique of choice to detect ectopic location and is also indicated for metastatic or locally recurrent disease. It is seen as focal area of abnormal activity. The sensitivity of MIBG scintigraphy for detecting pheochromocytoma is 80-90% with a specificity of 90-100%, but a positive MIBG scintigraphy should always be correlated with CT or MRI.
Reference:
Aiims-Mamc-Pgi'S Comprehensive Textbook of Diagnostic Radiology (3Vols)
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!