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Old 06-07-2011
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Question Neurofibromatosis question and strange answer!

A 23-year-old man known to have neurofibromatosis, type 1 (von Recklinghausen's disease), presents with a left lower quadrant abdominal mass and signs of neurologic deficits in his left leg. In the ensuing workup, it is determined that he has higher than normal values of catabolites of epinephrine and norepinephrine in a 24-hour urinary collection. He is currently normotensive. Before invasive steps are taken to biopsy and eventually remove his left lower quadrant abdominal mass, which of the following is the most appropriate next step in management?

A. CT scan of the head looking for meningiomas
B. MRI of his adrenal glands
C. MRI of the acoustic nerves
D. Radionuclide scans from the neck to the pelvis looking for extra-adrenal pheochromocytomas
E. Radiation therapy to the left lower quadrant abdominal mass

____________

The correct answer is B. The concern is that even though he is now normotensive, invasive steps might trigger a hypertensive crisis from the previously undiagnosed pheochromocytoma that he probably has. The presence of catabolites from epinephrine indicates that the tumor is in the adrenal glands, and not at an extra-adrenal site. Thus, the diagnosis of the pheochromocytoma can best be confirmed by MRI of the adrenals.

Meningiomas (choice A) and acoustic nerve tumors (choice C) occur in type 2 neurofibromatosis, not in type 1.

Looking for pheochromocytomas outside of the adrenal glands (choice D) would have been a good idea if only elevated catabolites of norepinephrine had been detected. The presence of high levels of epinephrine catabolites implicates the adrenal glands.

Radiation therapy (choice E) is a bad idea. Benign neurofibromas can be stimulated by radiation to undergo malignant transformation.


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Why not CT???? you have a focal neuro deficit ( I thought of meningioma) ... How come they ignored the leg thing!??!!? why did they even bring up the leg to start with? I realize its not extrapyramidal but the leg has something up with it ... what do u think?
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