Sunday, August 30, 2009

Pheochromocytoma


MRI abdomen of 14 year old male patient came with uncontrolled hypertension with raised urinary catecholamines showing well defined focal soft tissue intensity mass in the left supra renal gland having intensely hyperintense on T2 W image and hypointense on T1W image. Features are consistent with pheochromocytoma.

Pheochromocytomas are rare but treacherous catecholamine-producing tumors, which if missed or not properly treated, will almost invariably prove fatal. Prompt diagnosis is, therefore, essential for effective treatment, usually by surgical resection. The manifestations are diverse and the tumor can mimic a variety of conditions, often resulting in either erroneous diagnoses or a delayed diagnosis. Imaging is very essential for accurate diagnosis.
Pheochromocytomas are extra adrenal (10%), multicentric (10%), bilateral (5%), and malignant (10%)..Size is variable from 1-20 cm.The treatment is surgical excision of tumor, which is curative in all cases. The initial imaging findings in benign and malignant pheochromocytomas are nearly identical. Only the presence of metastasis can clearly define a lesion as malignant. On CT it appears as round or oval discrete mass with homogenous density. Similar findings have been noted in the present case. Central necrosis, calcification and cystic changes may be present in minority of cases. These vascular lesions enhance uniformly after administration of contrast material. MR is also excellent for evaluating intraadrenal pheochromocytoma.On T1, mass has intensity similar to or slightly less than solid organs. OnT2 lesion is hyper intense as result of their long T2 time. Sometimes adrenal metastases also present overlapping imaging findings. Combination of MIBG,CT and MRI scanning is definitive in the diagnosis of pheochromocytoma.

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