A year ago, a Potomac plastic surgeon tightened the sagging skin and wrinkles of middle age, and gave 55-year-old Mary Vassiliades of Bethedsa a new, youthful face.

Later, the surgeon, Dr. Csaba Magassy, appeared on a local television show and used photographs of his patient's face to illustrate the possible results of cosmetic surgery for older women. He also gave a lecture at Garfinckel's department store, entitled "Cream vs. Plastic Surgery," and display slides of Vassiliades' face.

Yesterday, Vassiliades filed a $33 million lawsuit in D.C. Superior Court, contending that as a result of that publicity, she was held up to a "public scorn" and suffered humilitation and loss of reputation.

The suit, filed against Magassy, Garfinckel's, Brooks Brothers, Miller and Rhoads Inc., and Metromedia Inc., contends that none of the defendants had Vassiliades' permission "to have her face displayed and discussed."

Magassy, who is also a general surgeon and a member of the teaching staff of George Washington University Hospital, said yesterday he was "shocked" by the suit.

"When I last saw Mrs. Vassiliades on Dec. 20, she was elated with the dramatic results of her surgery," Magassy said. "She gave me and members of my staff gifts because she said she was so happy with the job. And she told me to feel free to discuss her case or show photographs of the results to anyone who wanted to see what could be done with plastic surgery."

Reached at the Bethesda home yesterday, Vassiliades refused to comment on the lawsuit except to say, "Good God, no. I never gave him permission to use those photographs."

According to the suit, Magassy used photographs of Vassiliades on March 26 on "Panorama," a television program broadcast by WTTG (Channel 5), to demonstrate the "benefits of cosmetic surgery for older women . . ."

On March 29, according to the suit, Magassy gave a presentation at the Garfinckel's store at 14th and F streets NS to an audience that paid $3 each to attend the lecture. Slides showing Vassiliades' face were used in that demonstration, the court papers said.

Magassy said Vassiliades was one of two dozen of his former patients whose photographs were used in the Garfinckel's lecture.

The suit alleged that WTTG "received free program matter" and Magassy "received free publicity" through the use of her photographs.

Preston, Padden, an attorney for Metromedia, said that Magassy signed a standard release and idemnification agreement before he went on television, which relieved the corporation of any liability in the event of a lawsuit.

Magassy said he was asked by a Garfinckel's official to appear on "Panorama," and at the department store in connection with a special promotion being conducted by the store on beauty aids. Magassy said he was not paid for either presentation but did them as a "public service."

A spokeman for Garfinckel's could not be reached for comment.

"We had no indication that Mrs. Vassiliades was unhappy," said Diana Burton, Magassy's office manager. "Dr. Magassy is not hurting for business. He's booked up for surgery two months in advance and I talked with between 40 to 50 people a day who want an appointment with him." She said Magassy has seen about 10,000 patients during the seven years of his plastic surgery practice.

Magassy said Vassiliades had surgery last May 31 to tighten skin and remove excess flesh on her face, upper and lower eyelids and neck. Magassy said he charged Vassiliades $2,500 for the operation - not $4,000 as Vassiliades contends - and conducted his last examination of the results last Dec. 20.

On two occasions after the operation, Magassy said Vassiliades brought him gifts when she returned from trips to Greece, including Greek brandy and a pair of "worry beads."

Magassy said Vassiliades told him she was delighted with his work and told him that he could use her case and photographs as an example of his work.

Dr. Hubert Latham, president of the Metropolitan Society of Plastic Surgeons, an organization of 50 doctors of which Magassy is a member, said that the use of patients' photographs is a continuing source of problems for plastic surgeons.

"It is difficult to demonstrate what plastic surgery is without photographs," Latham said.