Minnesota hospitals have struggled for years to eliminate wrong-site surgeries, but just as soon as they think they’ve made progress, they find another gap in their safety protocols.

This time, the error occurred weeks before the surgery at Methodist Hospital, when the kidney on the wrong side was identified on the patient's medical charts as cancerous. The patient, whose name has not been released, was left with the cancerous kidney when the healthy one was removed last week.

“This is  tragic error on our part and we accept full responsibility for this. We feel just profoundly responsible for this,” said Dr. Samuel Carlson, chief medical officer for Park Nicollet Health Services, which owns Methodist Hospital, KARE 11 reported.

The surgery was performed last Tuesday, but only the next day a pathologist noticed the removed kidney was healthy. That’s when the patients was informed about the error.

"The discovery that this was the wrong kidney was made the next day when the pathologist examined the material and found no evidence of any malignancy," Carlson said.

The hospital has apologized to him and his family and “is working closely with them to support them in every way we can.”

The surgeon responsible for the situation has voluntarily stopped seeing patients. No other staff member has been removed from duty.

Hospital officials would not disclose what treatment the patient is following now because of privacy laws and the family’s request, but they said that when a patient has only one kidney that may be cancerous, you either try to save it and beat the cancer, or you have to remove it and start dialysis or consider a transplant. In some cases, Carlson said, cancer could make someone ineligible for a transplant.