IOWA CITY, Iowa – Meet Kid Captain Mya Gilchrist. After experiencing balance issues when she was 18 months old, Mya Gilchrist was diagnosed with a brain stem tumor and underwent surgery at University of Iowa Health Care Stead Family Children’s Hospital, where the tumor was found to be a cancerous form of pilocytic astrocytoma, a slow-growing brain tumor that originates from star-shaped cells called astrocytes.