Madonna Loses Appeal To Block Sale of Tupac Breakup Letter

Madonna just whiffed on her chance to shut down the sale of an old jailhouse letter from Tupac ... and now it looks like she's gonna have to watch as tons of her personal items hit the auction block.

According to new legal docs obtained by TMZ ... Madonna just lost her appeal to slam the brakes on the sale of the letter. A New York State Appeals Court ruled Madonna can't pursue claims against Darlene Lutz, her old pal and art consultant, or GottaHaveRockandRoll.com -- the online auction house to which Lutz consigned the items for sale.

Tuesday's court ruling opens the door for the sale of some of Madonna's intimate personal items, including the breakup note from her ex-boyfriend, Tupac.

As we reported ... last year a judge tossed out Madonna's lawsuit to stop the sale, saying a release she signed way back in 2004 means she couldn't sue over the letter's sale.

The appellate court upheld the judge's ruling in a 5-0 decision, saying Madonna's claims are blocked by the "very broad" release.

In his handwritten breakup letter, Tupac confesses he ended his sexual relationship with Madonna because she's white. Next month, it's finally going up for auction.