Search for patient's special toy ahead of chemotherapy treatment

Hannah Kiresuk, 19, was diagnosed with juvenile refractory myasthenia, a rare autoimmune neuromuscular disease, when she was a teen.

Through her four years of treatment, Hammy, a stuffed cow toy, has stayed by her side as she endured more than 30 surgeries and procedures. Hammy went missing Sunday and Kiresuk's family is hoping for the toy's safe return before her next chemotherapy infusion on Friday-- which would be her first without the beloved toy.

"Losing him is a BIG deal, hammy can't be replaced," Kiresuk, of Roseville, Minn., wrote on the Team Hannah's Courage Facebook page.

Hammy has undergone the same medical procedures as Kiresuk, including excision of the bone cyst, eye surgery, thymectomy, fistula placement, and tracheostomy. The cow was created at the Minnesota State Fair and Kiresuk made his hospital gown out of her favorite baby shirt and two of the zipper pouches were made from her cat's blanket.

"He can't be replaced, I need him," she wrote on Sunday.

Hammy is lost 󾍀Hannah needs hammy home! It will be her first chemo infusion without him if he's not back home Friday

For more: FOX NEWS