Personalized Personalized Histiocytosis Toddler Long Sleeve T-Shirt. Personalized Histiocytosis blue awareness ribbon design has room for a custom walk date or name. A classic for Fall, Winter and Spring, these long sleeve toddler t-shirts are sure to be a staple in your child's wardrobe. Whether layered or alone, this t-shirt is soft yet durable enough to stand up to your toddler's playtime demands.