New York. Dikembe Mutombo, a Basketball Hall of Famer known as one of the NBA's greatest defensive players and a devoted global ambassador for the sport, passed away Monday at the age of 58 due to brain cancer, the league announced. His family revealed two years ago that he was undergoing treatment for a brain tumor in Atlanta, and the NBA confirmed he died surrounded by loved ones.

"Dikembe Mutombo was simply larger than life," said NBA Commissioner Adam Silver. "On the court, he was one of the greatest shot blockers and defensive players in NBA history. Off the floor, he poured his heart and soul into helping others."

Mutombo was known for his playful finger wag at opponents after blocking their shots, his towering height, deep gravelly voice, and infectious smile. Players from the current generation admired him, including Philadelphia 76ers star Joel Embiid, who viewed Mutombo as a source of inspiration.

"It's a sad day, especially for us Africans and really the whole world," Embiid said. "Beyond his accomplishments on the basketball court, I think he was even better off the court. He was a role model of mine and has done so much for so many people."

Mutombo had an impressive 18-season career in the NBA, playing for teams including Denver, Atlanta, Houston, Philadelphia, New York, and the then-New Jersey Nets. The 7-foot-2 center from Georgetown was an eight-time All-Star and a three-time All-NBA selection, entering the Hall of Fame in 2015 after averaging 9.8 points and 10.3 rebounds per game.

"It's really hard to believe," said Toronto Raptors President Masai Ujiri, overcome with emotion after learning of Mutombo's passing. "You have no idea what Dikembe meant to me. He was a giant, an incredible person."

After retiring following the 2008-09 season, Mutombo dedicated himself to charitable and humanitarian work. He spoke nine languages and founded the Dikembe Mutombo Foundation in 1997, focusing on improving health, education, and quality of life for people in the Congo.

Mutombo served on the boards of numerous organizations, including Special Olympics International, the CDC Foundation, and the National Board for the U.S. Fund for UNICEF.

"There was nobody more qualified than Dikembe to serve as the NBA's first Global Ambassador," Silver remarked. "He was a humanitarian at his core, and he loved what basketball could do to positively impact communities, especially in his native Democratic Republic of the Congo."

Mutombo is one of only three players to have won the NBA's Defensive Player of the Year award four times, alongside current winner Rudy Gobert and Hall of Famer Ben Wallace.

Philadelphia 76ers president Daryl Morey, who spent many seasons with Mutombo in Houston, learned of his friend’s death during the team's media day. Tears filled Morey’s eyes as he processed the loss.

"There aren't many guys like him," Morey said. "Just a great human being. His accomplishments on the court are well-known, but what he did off the court for Africa is truly remarkable. Rest in peace, Dikembe."