Beastie Boys co-founder Adam MCA Yauch's death today at age 47 sent shock waves through the music world as millions of fans paid tribute to the rap pioneer.

Although Yauch's death came as a shock, his passing does not come as a surprise given his health problems, particularly the pituitary gland cancer he was battling before his death.

It's unclear whether the cancer was the cause of Adam Yauch's death.

Adam MCA Yauch made a heartbreaking YouTube video announcing the cancer back in July 2009 that had been viewed by nearly half a million users.

Yauch showed he had class in the video by apologizing to Beastie Boys fans who upended their schedules to see the group perform. The Beasties Boys had to cancel upcoming shows and push back their record release around the time Yauch made the video.

I guess I have some pretty heavy news to say, Yauch began in the video, which you can view by scrolling further down in this article. About two months ago, I started feeling this little lump in my throat, like you would feel if you have swollen glands, like you'd feel if you have a cold. I didn't really think it was anything.

Yauch said he was in Europe at the time doing promotional work when he called his doctor, who sent him to a specialist.

They did tests and I actually have a form of cancer in the gland that's over here, Yauch said, pointing to his neck. It's in a gland called the perotid gland and it's also in a lymph node in that area so I'm going to have to have surgery, probably next week.

Yauch said the lump did not affect his voice and called the cancer a little bit of a setback, a little bit of a pain in the ass.

News of Yauch's dead spread on Twitter, where trending topics including many Beastie Boys songs and albums such as License To Ill, Brass Monkey, Paul's Boutique, and Paul Revere.