Dr. Jan Adams operates out of the Brentwood Surgery Center -- which sits above a Kinko's and Quiznos in Brentwood, Calif.

BSC would not confirm that Donda West had her surgery there, however, TMZ spoke with an employee who told us that Dr. Adams was not in today (surprise) and she didn't know when he'd be back. Wait -- there's something wrong with the neon sign!

Dr. Jan Adams told TMZ Monday night he had done nothing wrong and that Kanye West's mother likely succumbed to a heart attack, pulmonary embolism, or from massive vomiting after returning home from surgery.