After a 40-year run as a teaching hospital, the Creighton University Medical Center is to be resuscitated as a mammoth apartment building with up to 700 units, open-air atriums, a rooftop pool and an enclosed retail corridor that looks out to a new lake.

NuStyle Development plans to add a couple of floors — expanding the midtown institution to 10 levels and 1 million square feet — solidifying it as the metro area’s largest single structure of market-rate apartments.