LAUSR

Anaplastic lymphoma kinase (ALK)‐positive histiocytosis is a rare disease that usually occurs in infants and young children and is characterized by ALK‐positive histiocytes infiltrating organs. We present a case of multisystem involvement of ALK‐positive histiocytosis in a female infant with skin nodules as the initial presentation. Despite multiorgan involvement, most tumors had spontaneously regressed, and all bones were partially healed after 40 months of regular follow‐up without treatment. However, gait abnormalities persisted, indicating that early treatment may have greater impact in maintaining a child's quality of life when the disease involves the brain or the critical period of bone development.