Ontario's health minister has weighed in on the pathology mix-up at Windsor Regional Hospital.

A woman who did not have breast cancer had unnecessary surgery because information in two patients' files was switched.

Barb Heartwell performed the surgery. She's the surgeon who mistakenly removed a breast from two healthy women.

In the latest error, the hospital said a pathologist's mistake is to blame. Hospital CEO David Musyj said he accepts full responsibility.

Health Minister Deb Matthews said it was right for Musyj to accept the blame.

"I was very pleased to see the CEO take full responsibility. We are focusing on quality when it comes to hospitals. Those quality indicators are important, because it's important to understand why something went wrong and to ensure it doesn't happen again," Matthews said.

 The pathologist who made the error is on leave while the case is investigated.