What began as a case of a doctor performing a mastectomy on a woman in error has now widened to several more "cases of concern" and a review of more than 10,000 pathology results in Windsor, Ont.

Hotel-Dieu Grace Hospital only became aware of the first mastectomy case through an inquiry from a reporter, then a second woman came forward after hearing a story so similar to her own.

The hospital started a review of Dr. Barbara Heartwell's cases and while she could not recall specifics, she told them they would find other incidents involving incorrect pathology reports, the hospital's interim chief of staff said Wednesday.

"During the course of our investigation she indicated that in our review of her past cases we would find additional cases of concern," Dr. Kevin Tracey said at a news conference.

The hospital also revealed it had been doing a pathology review since November and have uncovered seven serious cases of concern, five of which involve Heartwell's patients. Five cases involved breast cancer and two were unrelated.

The company providing the hospital with pathology services also serves two other area hospitals, and in January the hospital suspended the privileges of one pathologist, who was also reported to the College of Physicians and Surgeons of Ontario, Tracey said.

The pathology issues have so far been confined to that one pathologist, but as they expand the scope of the probe the hospital doesn't know what they may find, he said.

"We have no doubt that these revelations have prompted a high level of concern in our community," Tracey said.

"We share in that concern and will do all that we can to address individual patient issues."

Heartwell has voluntarily stopped performing surgeries pending the results of the probe, the hospital said.

Any patients with concerns about their care were asked to call (519) 255-2213.

The case of Laurie Johnston of Leamington, Ont., gained public attention last week after the Hotel-Dieu Grace Hospital announced it had started an internal investigation into what went wrong.

Janice Laporte, whose breast was removed by Heartwell in September 2001 but was told a week after her surgery that she didn't have cancer, came forward publicly after hearing about Johnston.

"At least things are being looked in to now," she said. "It's unfortunate that this has to happen for them to look into this kind of stuff."

Even though it has been nine years since Laporte's mistaken mastectomy, the emotional pain lingers.

"It's bad enough to have to be told you have cancer or to have a mastectomy," she said.

"That is devastating enough, but then to hear that it was done for no good reason just compounds everything."

A pre-surgery safety checklist that is in the process of being implemented provincewide would have made the difference in Johnston's case, Ontario Health Minister Deb Matthews said Wednesday.

"One of those items on the checklist before the anesthetic is given is a review of the biopsy," Matthews said.

"Implementation of that checklist would have prevented this terrible error."

The checklist will be standard practice in operating rooms provincewide by April, Matthews said, though she could not say why that would take five months as the measure was announced in September.

Dr. Michael Baker, executive lead for patient safety with the Ministry of Health, said there has been an educational period for hospitals, but that many are already using a checklist.

Heartwell admits she misread the results of a needle biopsy that found Johnston -- a single mother of a teenage daughter -- did not have cancer.

Johnston did not want to comment, but a litigation lawyer she has retained to look into her case said Johnston has been going through a "rollercoaster of feelings."

"She has obviously had a very difficult time coming to terms with what happened and she's trying to deal with it," said Barbara MacFarlane. "She's still coping with it, trying to process it all."

The hospital was not aware of Laporte's case until she came forward to the media. Laporte questions how that could happen.

"It troubles me," she said. "It sort of angers me, because I always assumed the hospital knew what their doctors were doing."

At the time of Laporte's case physicians weren't required to disclose something like that to the hospital, but that has since changed, officials said. Doctors are given privileges to work in the hospital but are independent practitioners, so some of their patient records are outside the hospital's domain, Tracey said.

Laporte filed a lawsuit over her case in 2002. She can't discuss the proceedings because of a confidentiality clause but the court case has ended, she said.

However in the statement of claim she filed Laporte alleged Heartwell performed "dramatic, disfiguring and invasive surgery" on her without informing her the pathologists who reviewed her tissue sample were seeking an outside opinion.

Heartwell's statement of defence said Laporte was given a copy of the pathology report -- which included the statement about an outside opinion -- and that Laporte chose to have a mastectomy "after being explained all of the risks, benefits and possible complications of the various treatment options."

The suit was settled before the allegations could be tested in court.