IGF-1 normal variant?

Hi, Doctor and thanks for starting this forum!  

In 2008, I was diagnosed by MRI with a 6 mm microadenoma, thought to be a prolactinoma.  A short while later, another MRI gave 4 by 6 mm measurement on the ill defined nodule.

In 2009, it was thought to have shrunk to 5 mm and was not big enough to be measured the other direction.  In 2010, it seemed to have disappeared from the pituitary altogether, but meanwhile, a an abnormal signal measuring about 6 mm showed up that a radiologist thought might be a pineal cyst.  

My prolactin during this time went down, down, down.  Meanwhile, my IGF-1 had been on a seemingly upward climb (though all in normal range).  

I also have two lesions on my liver, one is a slow growing hemangioma, and a second was hyper-echoic on ultrasound and not really big enough to figure out on MRI at 8 mm... hemangioma, complex cyst or focal nodular hyperplasia have all been possible guesses by the radiologist.  Cancer markers have been negative.

Here are my IGF-1 numbers all done at different labs all in normal range but with a recent swing upward:
2/19/2008:   214 ng/mL
(Ref for ages 31-40 106-368, mean 225, SD 71)

3/31/2009:   234 ng/mL
(Ref range- not age specified 109-284)

9/18/2010:   272 ng/mL
(Ref range- not age specified 64-334)

Would it be possible that the microadenoma had been depressing my growth hormone, and thus IGF-1 levels, and now that the tumor seems to have disappeared, the IGF-1 went up to what would be my normal level (though higher than the median listed in the age sensitive reference range)?

Could it be that this possible pineal cyst or the liver lesions could account for the upswing in IGF-1?

I heard that IGF-1 can be affected by tumors and I know it is synthesized by the liver.
However, is it completely normal and not at all uncommon to have your IGF-1 go from 214 to 272 in the above span of time and if so, what are/is other reason(s) it does that sort of thing?

[Daniel M Prevedello, MD]

Dear SurgiMenopause.

You don't have to worry about your IGF-1 results. They are great. they are all in the normal range. One result cannot be compared to the others. As you can see the normal range also changes from one test to the other. It doesn't mean that it is increasing. It means that it has been normal.
You are a lucky person since your pituitary lesion disappeared.