Wednesday, August 12, 2009

The Rule of 10's

I suppose it was about time.
I saw this case recently, of a patient with a history of phaechromocytoma (UK-spelling intentionally used). This was resected over a decade ago, and she was then lost to follow up. Has been doing well, totally asymptomatic. And then someone recently decided to do some screening tests. Her serum metanephrines were through the roof.
When I saw her, I repeated the test along with a 24-hour urine study, since these are often prone to false positives. Again, over 10x above normal. An MRI abdomen was negative, so I ordered an MIBG scan which came back positive for multiple mets to the skeleton.
Phaes are rare; they say most practicing physicians may see only one in their careers. Yet, despite the rarity of this, all exams seem to contain at least one phaeo question. And all medical students know the Rule of 10s for phaeos: 10% bilateral, 10% in childhood, 10% extraadrenal, 10% metastatic.
This would have been probably my 12th case in my career. Simply by probabilities I suppose it was time I saw my first metastatic case though I have been dreading this day. I will not have much to offer this patient though I am hoping that a bigger, academic medical center may have some experimental trial they can enrol this patient in.