ROME (AP) — It's a story almost too fantastical to be true: A flea market dealer finds a painting near a subway trash bin, submits it to laboratory analysis and emerges convinced he has a Modigliani on his hands.

No one would believe it, given the modernist master is one of the most sought-after and forged artists around.

But a public relations firm in Rome that doubles as the Amedeo Modigliani Institute is claiming a signed portrait of "Odette" could be a real deal. It's putting the work on public view next week saying it hopes to start an academic debate on its authenticity.

"I assure you, this isn't a fake and we are dealing with a discovery," insisted Luciano Renzi, the institute's president and head of an eponymous publicity firm. While acknowledging that experts must make such a certification, he said he wouldn't put it up to critical review "if the institute didn't firmly believe it."

However, the institute has no role or expertise in authenticating Modigliani works, has a financial interest in drumming up publicity for its exhibit, and even the lab it hired refuses to date the painting.

Amedeo Modigliani died in 1920 in Paris at age 35 of tubercular meningitis after a short but intense career that produced masterpieces: portraits, nudes and sculptures, many featuring the distinctive lithe necks of his muses. The most authoritative catalogue of his works, completed in 1972 by critic Ambrogio Ceroni, lists 337 known pieces.

The timing of "Odette's" appearance is certainly suspect: In November, Modigliani's "Nu Couche" ("Reclining Nude") fetched $170 million at a Christie's auction in New York, the second highest price ever paid for an artwork at auction. A host of museum exhibits around the globe are planned in the run-up to the 2020 centenary of his death.

And it comes as the Amedeo Modigliani Institute tries to recover from a credibility scandal involving forgeries and its past president, Christian Parisot, who was arrested in 2012 on charges he knowingly authenticated fake works. Parisot and Renzi founded the institute a decade ago to house the artist's documentary archive, which had been bequeathed to Parisot by Modigliani's only daughter. The institute wasn't implicated in the scandal, but its reputation suffered by association.

Experts cautioned that any purported Modigliani must be greeted with an overdose of skepticism, given the propensity for hoaxes, fakes and forgeries and the financial interests of all involved. Most significantly, "Odette" has no provenance, or paper trail of past owners, rendering it virtually unsellable by any reputable gallery and problematic for any serious scholars to consider.

"It's extremely rare that a work would pop up out of nowhere without any previous trace," said Kenneth Wayne, a leading Modigliani scholar who heads the Modigliani Project in New York. "If a work just appears in 1990 or 2016 without any history whatsoever, no exhibitions, no programs, that's a major cause of concern. It's a red flag."

The institute and the painting's owner point to two sets of laboratory analyses that they claim date the painting to the first two decades of the 1900s, during the artist's lifetime and before the first Modigliani copies started to appear. The analyses show no trace of titanium white, which only came into use in 1924 and would be a tell-tale sign of a fake given Modigliani's death four years prior.

The analyses point to the wood frame, canvas, colors and surface dirt as being consistent with the era in which Modigliani lived, said Alberto D'Atanasio, a docent at a Brescia art academy who was brought in by the institute to give an artistic assessment before going public.

"We don't know anything about this painting," conceded D'Atanasio, who is not a Modigliani expert. "Nevertheless, nothing, nothing makes me think this is a fake."

But even the laboratory hired by the institute refuses to make any claim about the painting's age based on its analysis.

"The paint suggests an ageing — years have passed — but to bring it back to 100 years, we can't do anything like that," said Luana Casaglia, restorer at the Cooperativa Beni Culturali in Spoleto. "It would be risky for us to say that."

Wayne, who hasn't viewed the painting, noted that the absence of titanium white doesn't exclude a more recent forgery using old paint. He also noted that "Odette's" measurements — 73x54 centimeters (29x21 inches) — aren't found with any consistency in the Ceroni catalogue. Modigliani's portraits often measured 100x65 centimeters, he said.

The owner hasn't come forward publicly, another red flag. His Rome-based lawyer, Gennaro Arbia, says only that his client is a flea market dealer who in June 2006 found the painting resting up against a trash bin at the La Rustica metro stop in Rome's periphery. Rats had gnawed some holes in it.

Arbia, who previously represented a man claiming to be the son and heir of painter Renato Guttuso, said he sent a photo to Parisot's Paris-based operation in 2006 hoping to get it certified. Parisot's office responded saying there were no elements to suggest it could be authentic and declined to analyze it further, Arbia said.

His client persisted and 10 years later Arbia approached the Rome institute with a first set of lab analyses. The institute then hired the Spoleto lab for a more invasive analysis of the paint and accumulated dirt.

Arbia freely admits his client wants to sell the work, even though he would be hard pressed to find a collector willing to spend serious money for a painting with no provenance. The institute, too, has a financial stake in promoting it given the publicity for its upcoming exhibit of Modigliani reproductions at a Spoleto arts festival where "Odette" will be shown.

And all involved concede that Modigliani hoaxes abound: One of the greatest involved the "discovery" in 1984 of three sculpted heads purportedly tossed by the artist into a canal in his hometown of Livorno. Three young men eventually confessed to having carved the heads themselves with power drills and tossed them in as a joke.

What if "Odette" is found to be a fake?

Arbia pauses. "The dream is over."

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