WALNUT CREEK, Calif. — To their surprise, University of California, San Francisco researchers have discovered a new type of cell in women’s breast tissue that might one day be used to heal a variety of wounds and damaged organs, without having to destroy embryos to acquire stem cells.

The newly discovered cells act similarly to embryonic stem cells in that they can be placed in mice or in a Petri dish and “instructed” to produce many different cell types.

That raises hope that the cells might someday be used as a sort of personalized “patch kit,” without the controversy that has surrounded stem cells taken from human embryos.

“When we saw that they could make cartilage, bone, gut, brain, pancreas cells — even beating heart tissue — we were excited and intrigued,” said senior study author Thea Tlsty, a UCSF professor of pathology.

“We were not looking for this,” she said. “This was unexpected.”

The study was published Monday in the online early edition of the Proceedings of the National Academy of Sciences.

Scientists had previously believed that so-called pluripotent cells, which can transform into most cell types, did not exist in the body beyond the embryonic stage of development.