MIsspelled signs and stuff

One of my favorite things about driving home to Chicagoland is looking out the window as the bus chugs down the Expressway. Although the view is mostly farmland, there are always amusing billboards to look at to keep entertained.

Usually, the amusing billboards are the ones advertising adult enterntainment stores or Amish villages. They seem more earnest and real, unlike the corporate ads that pop up every five feet once you hit the outskirts of the city.

But this Friday, the most amusing billboard I saw came from the unlikliest of places.

There was a picture of a little girl, and the caption said "Diana vs Leucemia."

Immediately I did a double take. But since we were driving, I couldn't exactly look back to see if I saw what I thought I saw. But I was fairly certain they spelled Leukemia wrong. How could they do that? What kind of bozos don't check the spelling of a cancer billboard? It's one thing to misspell something in a beer billboard, but cancer?

When I got home, I looked online to see if I was correct my spelling of Leukemia.

Yes, I was correct.

But I was wrong about the billboard. In fact, Leucemia is an alternate spelling of Leukemia.

Whoops. Apparently I shouldn't have patted myself on the back after all.

But it reminded me of an article I read last year in the Chicago Tribune about a group of friends whose hobby was to drive around Chicago and find all the grammatical errors on signs, billboards, businesses, etc. They took photos and created a website to document it and, and for the life of me, I can't find it.

Anyway, back to my Leukemia/Leucemia problem. I think that more people refer to the disease with a "k" instead of a "c." I must admit that I'm partial to it, since people often think my last name starts with a "c."

Regardless, if there are two common spellings, how do you know what to refer to it by? The AP Stylebook doesn't have a Leukemia/Leucemia entry, so are both correct? I suppose they are. But perhaps diseases should be dealt with differently, since spelling it two ways may make it seem as if you're talking about two different diseases. Who knows...