Abby suffers from pre-B cell acute lymphobastic leukemia. She met nurse Matt Hickling at the Albany Medical Center's Melodies Center for Childhood Cancer in Albany, N.Y.
"They have always had a great connection since the beginning of her [diagnosis]," reads a post from her Facebook page, Amazing Abby. The page shows multiple photos of Abby's nurses, including Hickling, taking great care of her.
A few days before the ceremony, Abby kept saying she was going to get married that week. When her mother pressed Abby to answer who she would be marrying, Abby said Hickling.
Her mother texted Hickling to give him a heads up about Abby's romantic plans.
"This took me by surprise," Hickling wrote on his Facebook page.
That's when Hickling sprang into action. In less than a day, he and the staff at the hospital planned and executed the four-year-old bride's dream wedding.
The little bride wore a shiny white dress and headband to the nuptials on Thursday. She carried a bouquet of pink and red flowers donated by a local florist.
She approached Hickling, who donned a tuxedo T-shirt for the occasion, and shyly asked him if he would marry her. When he said yes, she embraced him in a giant hug.
The pair exchanged candy rings, and Hickling pushed Abby in a special "Just married" pink car before the duo headed back to the ceremony room to cut the cake.
"This day will hopefully be one our patient and her family can always look back on and smile when days are tough," wrote Hickling. "I know I will."
As for the little bride, she seemed pleased with her first wedding.
Both Hickling and Abby's Facebook pages say she called it "the best day ever."
"We are both in awe from today's visit and smiling ear to ear," wrote her mother.