Alexis Ohanian, tennis legend Serena Williams' husband, detailed a recent health scare in a post on Instagram ... in which he says he got half his thyroid removed.
The Reddit cofounder and entrepreneur explained it all in a post put up on Thanksgiving day ... showing a snap of him with a scar on his neck while gowned up in a hospital bed -- saying the procedure came after "tracking some suspicious nodules on my thyroid for the last 4 years."
Alexis says the nodules kept getting bigger over time, and his most recent biopsy revealed "they’d very likely turn cancerous" -- adding he wasn't going to take a chance.
Serena's hubby pointed out his personal connection to cancer, too -- saying, "My mom had breast cancer around this age (41) and then ultimately died from brain cancer a decade or so later. I hate cancer."
All in all, Alexis says the surgery went well and claims the worst part is not being able to lift for 2 weeks -- obviously, a small price to pay compared to what he was risking before it got removed.
Alexis finished his post by urging his "fellow men" to get checked out, "especially if y'all are dads" ... before wishing everyone a happy Thanksgiving.
He also included pics of his kids -- 6-year-old Olympia and 1-year-old Adira -- in the post ... and we're guessing his kiddos, his wife Serena, and good health are all things he's thankful for this year.