× These pituitary tumors (also called adenomas) secrete excessive amounts of prolactin and are the most common type of pituitary tumor seen clinically.

When is tumor shrinkage abnormal?

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When is tumor shrinkage abnormal? was created by JMiller

I was diagnosed with a macro prolactinoma in February 2017 after it was spotted on a CT, and confirmed with MRI and lab work.  Other than lack of libido I was otherwise asymptomatic.  I went to the docs for what I thought was a neurological issue which was eventually diagnosed as non-epileptic seizures.  We're still unraveling that mess.

Initial prolactin number was over 1500 ng/ml, tumor size was 20mm x 19mm x 16mm.  The tumor had caused the sella to expand.  A ton of other blood work and other testing was done to rule out other possible disorders.  Additionally, my weight was sitting at 235 pounds, up from 180 pounds in May 2011.

I was put on Cabergoline .5mg twice a week.  By May 2017, the prolactin number was down to 3 ng/ml and the tumor had dropped to 14mm x 17mm x 10 mm. 

Over time the prolactin number has stayed within the normal male range.  The tumor had steadily shrunk down to 10mm x 12mm x 6 mm in December 2018.  Over those two years I had four more sets of imagery done at three different facilities and all reflected a steady decrease in tumor size.  My weight had also fallen to 178 pounds and I have stayed in a 178-188 pound range ever since.  All other nutritional bloodwork (A1C, blood glucose, cholesterol, etc) are in the very healthy range.  

In December 2018 my dosage on the Cabergoline was reduced to .25mg twice a week because the side effects were still pretty ugly--on .5 mg I all but lost my Sunday afternoons and Wednesday evenings.  Today the side effects are far more manageable.

I moved to a new town this past March and  had my annual MRI this week.  The prolactinoma, as read by the radiologist, measured at 2.8mm x 1.9mm (on the anterior interior aspect), but the radiologist also interpreted the imagery to have a pars intermedia cyst present at 1.7mm x 1.0mm (posteriorly and inferiorly) which had not been seen in six previous MRIs.

If the numbers are true, I should be happy as can be with the progress.  But twice the linear progress in 11 months with half the medication than I had in the previous 18 months with twice the medication doesn't make sense to me.  But I'm also an engineer, not a medical specialist so I could be looking  at that silver lining and wondering what the rain cloud isn't big enough.

I've asked my endocrinologist about the results and he seems to be nonchalant about the whole thing.

Is this big of a drop in linear size normal?  What am I missing?
2 years 3 weeks ago #10793

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