A West Dennis woman pleaded not guilty Tuesday to prostitution and larceny charges for allegedly stealing a $500 necklace from a 90-year-old man after he hired her to perform a sexual act, police said.

Karen Proia, 48, allegedly stole the chain from the man’s bathroom after the two engaged in a paid sexual act, Dennis Police Lieutenant Peter Benson said. The man reported the theft to police on June 30.

Police later found the necklace at a local pawn shop, Benson said. They advised the man that if they charged Proia with larceny, they would have to charge him with soliciting a prostitute.

“He used harsher terms, but he said that was fine,’’ Benson said. “He said if that’s the way it has to be, then that’s the way it has to be.’’

Both Proia and the man were arraigned in Orleans District Court on Tuesday. Proia was charged with prostitution and larceny over $250, and prosecutors dropped the man’s charge of soliciting a prostitute.

“The attorney in court who was handling the arraignment made the decision because of the age of the individual, his difficulty hearing the judge, and his overall infirmity — he was being helped around the courtroom — to dismiss the case against him,’’ Cape and Islands District Attorney Michael O’Keefe said.

“I would say there’s not too many soon-to-be 91-year-olds who are prosecuted for anything,’’ O’Keefe said.

Proia is due back in court for a pretrial hearing on Sept. 1.

Dylan McGuinness can be reached at dylan.mcguinness @globe.com.