The Hospital Authority has set up a team to investigate an improper mastectomy operation involving a 36-year-old woman at North District Hospital. The report is due out in six to eight weeks.

On July 30, the patient was diagnosed as having developed a mass in her left breast, based on her clinical condition, a private investigation and the X-ray results.

To plan for proper treatment and confirm the nature of the mass, she had a breast biopsy on July 31 that indicated it was malignant.

Following discussions with the patient's relatives, a left mastectomy operation was successfully performed on August 26 and the patient was discharged on September 2.

However, a pathological review of the breast tissue afterwards did not match the initial tissue investigation results before the operation. Repeated investigations from September 3 to 11 confirmed the tissue had no malignancy.

A DNA test on the pre-operation breast tissue showed the malignant specimen was not hers.

The hospital met with the woman's family this morning, explained the incident, and expressed sincere apologies. The patient was reassured she would have the best care and treatment in the follow-up of her clinical and psychological condition.

A thorough check on other patients' record showed no other patient was affected by the incident at this stage. The hospital has immediately reviewed the operational procedures and reminded departments and staff to strictly follow protocols and guidelines to avoid a similar incident.