The set of six X-rays and a file of doctors' notes that offer a partial medical history of the "Gentlemen Prefer Blondes" actress from 1950 to 1962, are expected to fetch between $15,000 and $30,000 at auction on November 9-10, said Julien's Auctions in Beverly Hills, California.
The notes written by Hollywood plastic surgeon Michael Gurdin appear to confirm speculation that Monroe, who epitomized glamour and set a standard of movie star beauty during the latter part of Hollywood's golden era, went under the knife for cosmetic reasons.
The seller, who is so far unnamed, received the items as a gift from Gurdin.
"Nobody really thought about Marilyn Monroe having plastic surgery. It was always speculation - did she or didn't she?" said Martin Nolan, executive director of Julien's Auctions. "They thought she was such a natural beauty, they didn't want to believe."
Gurdin's notes include references to a 1950 cartilage implant in Monroe's chin, which he observed to have slowly begun to dissolve.
Monroe's biggest films, such as 1953's "How to Marry a Millionaire," 1955's "The Seven Year Itch" and 1959's "Some Like It Hot," were all shot after 1950.
"Also at that time, going back to the 1950s, people didn't go for plastic surgery procedures," Nolan added. "This is very, very new."
THE BROKEN NOSE MYSTERY
The X-rays are dated June 7, 1962, after Monroe saw Gurdin following a late night fall and two months before the actress would die at age 36 from an overdose of barbiturates. The death was ruled a probable suicide.
Monroe would also be fired by studio 20th Century Fox from the unfinished film "Something's Got to Give" the following day for her constant absences.
The X-rays include Monroe's frontal facial bones, a composite right and left X-ray of the sides of her nasal bones and dental X-rays of the roof of her mouth.
A set of three chest X-rays of Monroe from 1954 sold for $45,000 at a 2010 auction.
A self-published memoir by Beverly Hills plastic surgeon Norman Leaf in 2010 claimed that Monroe underwent cosmetic surgery on her chin in 1950, citing the same notes made by Gurdin, Leaf's medical partner.
Leaf also states in his memoir that Monroe underwent a slight rhinoplasty procedure on the tip of her nose.
A radiologist's notes included in the lot determined that there was no damage to Monroe's nose from the fall, but a recent evaluation of the X-rays found a minute fracture, the auction house said.
Doctors used the name "Joan Newman" as Monroe's alias on the X-rays which list her height as 5 feet, 6 inches (1.68 m) and her weight as 115 lb (52 kg).
Gurdin's notes were first drawn up in 1958 when the actress complained about a "chin deformity" and the note listed her married name, Marilyn Miller. She was married to playwright Arthur Miller from 1956 to 1961.
The notes also indicate that Monroe suffered from neutropenia, a low level of a white blood cell type, in 1956 while in England and had an ectopic pregnancy in 1957.