Now, after years of unsubstantiated rumors about Louis C.K. masturbating in front of associates, women are coming forward to describe what they experienced. Even amid the current burst of sexual misconduct accusations against powerful men, the stories about Louis C.K. stand out because he has so few equals in comedy. In the years since the incidents the women describe, he has sold out Madison Square Garden eight times, created an Emmy-winning TV series, and accumulated the clout of a tastemaker and auteur, with the help of a manager who represents some of the biggest names in comedy. And Louis C.K. built a reputation as the unlikely conscience of the comedy scene, by making audiences laugh about hypocrisy — especially male hypocrisy.

[ Read Louis C.K.’s statement: “These stories are true” ]

After being contacted for an interview this week about the on-the-record accusations of sexual misconduct — encounters that took place over a decade ago — Louis C.K.’s publicist, Lewis Kay, said the comedian would not respond. “Louis is not going to answer any questions,” Mr. Kay wrote in an email Tuesday night.

Neither Louis C.K. nor Mr. Kay replied to follow-up emails in which the accusations were laid out in detail, or to voice messages or texts. On Thursday, the premiere of Louis C.K.’s new movie “I Love You, Daddy,” was abruptly canceled, and he also canceled an appearance on “The Late Show With Stephen Colbert.”

The stories told by the women raise sharp questions about the anecdotes that Louis C.K. tells in his own comedy. He rose to fame in part by appearing to be candid about his flaws and sexual hang-ups, discussing and miming masturbation extensively in his act — an exaggerated riff that some of the women feel may have served as a cover for real misconduct. He has all but invited comparison between his private life and his onscreen work, too: In “I Love You, Daddy,” which is scheduled to be released next week, a character pretends to masturbate at length in front of other people, and other characters appear to dismiss rumors of sexual predation.