Northeast Patients Group has signed a lease to open its Portland medical marijuana dispensary at 685 Congress St.Becky DeKeuster, executive director of Northeast Patients Group, confirmed the lease for the roughly 6,500-square-foot space but didn't reveal more details about the dispensary or when it will open for patients, saying she'll provide more information in the coming days. She said her organization has plans to redesign the vacant space, which is near Longfellow Square, and still must go through the city's permitting process.