Enlarged Liver, 25yo male, non-drinker. What's wrong?

I am a 25 year old male Caucasian.
I had an ultrasound to check on gallstones which were originally found 4 or 5 years ago. The u/s showed "Cholelithiasis is demonstrated", "Incidental adenomyomatosis of the gallbladder." and "Borderline hepatomegaly." . The report also says "The liver is at the upper limit of normal for size, right lobe measuring 15.5cm. The liver is smooth in outline and homogenous in echotexture with a normal echo pattern. No focal hepatic mass. No splenomegaly. No ascites.".
Also, my liver enzymes WERE elevated around 4 Oct 2012, but most were back in normal ranges by 3 Dec 2012 except for GGT which was 65 U/L (slightly less than than the Oct reading of 72).
I do not drink and have only tried (one or less than one standard drink) alcohol two or three times during my lifetime.
Recent STD check showed no Hepatitis STDs.
I am worried about my liver. What could be wrong, if anything? What follow up tests should I now get done?
Additional possibly useful info: I weighed 85 to 87 kg around March 2012, between May and July I got my weight down (intentionally with a low/almost zero carb diet) to 68kg and have been around 68 to 70 kg since that time.

[Thomas D Schiano, MD]

it is possible that you had some slight fatty liver and by losing the weight you normalized the liver tests

[AusFrog]

Should I be worried at all? Do I need my gallbladder taken out?

[AusFrog]

Some extra info: I just got a copy of the 2009 ultrasound report and it showed "a small mobile gallstone 0.7cm" and also mentioned "Liver, spleen, ..., all appear sonographically normal". So if my liver was normal back in 2009 and is now in 2013 borderline enlarged, that would imply MY liver has enlarged sometime between 2009 and 2013.
What tests can I get done to determine a cause for my liver enlarging and/or to rule out some of the more nasty causes like cancer or heart problems or autoimmune etc etc?

[Thomas D Schiano, MD]

i do not think that you need to remove the gallbladder.  Serologic blood test to exclude viral hepatitis should be done.  an MRI may be a good noninvasive assessment for fat and scarring

[AusFrog]

So I don't need it out? Not even with a little bit of minor/dull pain at the front and sometimes at the back around the area of the gall bladder every now and then?
(Sorry, I had thought I mentioned that in my original question; that was the reason to get the ultrasound in first place.)

[Thomas D Schiano, MD]

i wouldnt take it out at the current time

[AusFrog]

Thank you so much for your reassuring responses.
One last question-- What type of specialist/s would I want to see for lithotripsy or for contact dissolution therapy (or any other treatment that isn't going to include removing the gallbladder)?

[Thomas D Schiano, MD]

gallstone dissolution is no longer performed with lithotripsy.  

[AusFrog]

Are either performed individually?

[AusFrog]

What are the non-surgical options I would have?