SAN FRANCISCO — Officials at San Francisco General Hospital confirmed Tuesday that they had discovered a woman’s body on a rarely-used exterior stairwell, raising fears that the body may be that of a San Francisco woman who went missing three weeks ago while being treated at the hospital.

The body was discovered about 10 a.m. on the fourth-floor stairwell, according to a statement from the hospital. Officials did not say if they could determine the cause of the woman’s death or how long it had been since she died.

A spokesman for the family of 57-year-old Lynne Spalding said the family had received a call notifying them of the discovery of the body this morning but that hospital officials did not confirm that the body was Spalding’s.

A family spokesperson said Tuesday evening that an official with the San Francisco Medical Examiner’s Office said that the identity of the body had not yet been confirmed.

Spalding was last seen about 10:15 a.m. Sept. 21 by hospital employees who were treating the woman for an infection. A native of Britain, Spalding worked in the hospitality and travel industries in San Francisco in recent years.

“She’s very well known in the tour industry,” family spokesman David Perry said. “Everyone knows Lynne. She sold San Francisco. Her job was to represent our city.”

Perry said Spalding’s boyfriend and daughter took her to the hospital because she had recently begun losing a lot of weight and “did not seem like herself.” Hospital personnel admitted her and began treating an infection; she was hospitalized for two days before she went missing.

Friends speculated that drugs given to her at the hospital were “making her a bit dopey,” and that she may have wandered away from the hospital in her altered state, Perry said. A search party spent more than a week canvassing the city with fliers bearing Spalding’s picture.

“Her family and friends are just devastated,” Perry said. “They’re frustrated and apprehensive. If we had known she might still be in the hospital, we would never be out canvassing the whole city. We would be searching the hospital.”

While S.F. General said there was “no video evidence” of the woman leaving the hospital, there was also no indication that cameras were even present on the floor. An S.F. general spokeswoman was unavailable for comment Tuesday evening.

“I feel awful for S.F. General staff — they must feel under assault,” Perry said. “But we need some answers so we can prevent what happened from happening again.

“Of all the scenarios, this one never occurred to me. This is a nightmare. I’m still in shock.”

Contact Erin Ivie at eivie@bayareanewsgroup.com. Follow her at Twitter.com/erin_ivie.