Dwyane Wade Reveals He Had Surgery to Remove Cancerous Tumor, 'Took 40% of My Kidney'

SCARY DISCOVERY The Why with Dwyane Wade

Stunning revelation from Dwyane Wade ... the NBA legend says he had to have nearly half of one his kidneys removed from his body in order to rid himself of a cancerous mass.

The 43-year-old Hall of Famer said on the most recent episode of "The Why with Dwyane Wade" he had the procedure done roughly 13 months ago ... after he went to a doctor for a checkup.

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Wade said he had been having some cramping issues in his stomach -- and he'd also been battling some problems with his urine stream.