Former Concacaf leaders Jack Warner and Chuck Blazer have been described as "fraudulent in their management" by the head of the body's integrity committee David Simmons.
Warner resigned as Fifa vice-president in 2011 after bribery allegations.
Simmons said Warner failed to disclose a $25.9m (£17m) centre of excellence was built on his land and that Blazer received $20m (£13.3m) from Concacaf.
"I have recounted a sad and sorry tale in the life of Concacaf," Simmons said.
"[It is a] tale of abuse of position and power, by persons who assisted in bringing the organisation to profitability but who enriched themselves at the expense of their very own organisations."
Concacaf, the continental governing body for football in North America, Central America and the Caribbean, is examining its legal options over the building of the Trinidad and Tobago centre of excellence.
Neither Warner or American Blazer, who resigned as Concacaf general secretary in 2011 and is standing down from Fifa's executive committee, co-operated with the investigation, which was based on documents and 38 interviews, and both men have denied any wrongdoing.
Former Concacaf president Warner stood down from his role with Fifa in 2011 after being alleged, along with Fifa member Mohamed Bin Hammam, to have paid bribes of £600,000 to Caribbean associations.
At the time he was suspended by Fifa but his decision to resign meant that all investigations into him were closed.
Simmons's report found that Warner, who is now his country's national security minster, did not disclose that the Havelange Centre of Excellence in Port of Spain, which was built with £17m of Concacaf funds and Fifa loans, was situated on land owned by his companies.
Simmons claimed that in deals related to the centre, Warner "deceived persons and organisations" into believing the facility was Concacaf's and not his.
He said: "Approximately $26m of Concacaf funds went into a centre of excellence and that is no longer an asset of Concacaf.
"Warner represented to Fifa that funds would be used to support development but never told Fifa that centre would be situated on land owned by his companies."
Simmons stated that Blazer received $17m (£11.1m) in commission during his time with Concacaf and could find "no business reason" for Blazer renting an apartment in New York and attempting to buy property in the Bahamas worth $4m using football funds.
Blazer was also said to be "entirely negligent" for failing to file income tax returns for Concacaf in the United States, leading to the body losing its tax-exempt status as a non-profit organisation.