Iron Mike........Sued?

Just when.....when is Mike Tyson....ever going to get a break.

They say, "You make your own luck".........But ....Mr. Tyson.....seems ...to have...no luck at all.

A 49-year-old retired boxer is trying to pick a $115 million fight with Mike Tyson -- claiming "The Hangover" star hijacked his "Iron Mike" nickname 25 years ago.



The other "Iron" man is Mike Landrum -- a former professional fighter who claims he coined the nickname "Iron Mike" before he turned pro in 1983. Tyson started fighting professionally in 1985.

Landrum has filed a lawsuit in federal court in Los Angeles, claiming he owns the trademark to the nickname "Iron Mike" -- and therefore, Tyson infringed on his rights by using the nickname throughout his boxing career.

Landrum -- who's representing himself in the case -- tells us he was "hindered from getting any major title fights or sponsorships because of the name confusion."

For the record -- Landrum's record was 6-4 as a pro.

TMZ spoke with Tyson's rep Tammy Brook who tells us, "Mike's legal team hasn't seen the paperwork yet, but they are confident the case holds no merit."