This technically is a news story, since I found it on Reddit. Although I haven't actually found a good link to any other site reporting on it, the guy at least was gracious enough to give his personal account about his giant spleen in the comments to that picture.
So in 2009 this guy started just losing weight at a very quick pace. He said he would keep eating constantly, but he'd just keep losing weight and sweat a lot. (As a side effect though, he said he got the most kickass 8-pack abs, pictured here).
Well, as you might imagine, he started getting chest pains. After going to the doctor he found out that he had Chronic Myelogenous Leukemia, a disorder that basically makes new white blood cells that are not programmed to die, so the spleen decides to retain all of them. And to facilitate this, it needed more energy, hence the guys weight loss, and more space, hence the giant spleen. Apparently he had so many white blood cells that the surgeons had to thin his blood twice to make it operable.
Long story short he gets his spleen removed, and you can see it at the top of the page if you didn't already. Apparently it was so big that it was crunched up against his abdominals and ribcage, which is why he got that 8-pack.
Fast forward to 2011. The guy says he's got the paperwork filed to Guinness World Records as the "heaviest spleen removed" and is just currently waiting on his medical documentation to reach them. Once it gets to them, this guy will be immortalized in history. As the guy with the really huge spleen.
And apparently you can also live without a spleen. Anyway, this story is pretty much just chock full of bizarre if you ask me.
(Source)
