At his next visit in February, he was seen by another young woman, whom he also took to be a physician. As it turned out, both women were physician assistants.

The second physician assistant told Mr. Dalman that he would need radiation on basal cell carcinomas on his temple, shoulder and ear. He said he tried to argue with her, explaining that he’d had many similar lesions in the past that were removed with a simple scrape.

He said she countered that if she attempted to remove the lesion above his right eye, he might end up unable to blink that eye. And without superficial radiation on his ear, he was in danger of losing the entire ear. She said he would also need Mohs surgery on several of the basal cell carcinomas. She did not respond to requests from The New York Times to speak about the case.

Although Dr. Masessa signed Mr. Dalman’s chart, Mr. Dalman never met him. This could be because the clinic he went to, northwest of West Palm Beach, Fla., is one of more than a dozen clinics scattered across three states associated with Dr. Masessa, who is based in New Jersey but licensed in Florida. Supervision of physician assistants is required by state law. The Florida Department of Health website lists Dr. Masessa as supervising four physician assistants in the state.

Dr. Masessa did not respond to repeated requests for comment. An associate, who identified himself as Jeff Masessa, returned a call and asked for questions by email. Neither he nor Dr. Masessa responded to a detailed list of questions, despite repeated follow-up emails from The Times.

On the day of Mr. Dalman’s surgery, the same physician assistant injected a local anesthetic, then instructed Mr. Dalman to return to the waiting room, Mr. Dalman said.

Then something dawned on him. Since he had not laid eyes on a physician in several visits, he worried that the physician assistant would be doing the procedure. The prospect made him nervous and he decided to make a swift exit.