Background Lymphocytic hypophysitis (LYH) is a rare inflammatory disease of the pituitary gland that usually affects women in their ante- or immediate postpartum period; males are affected less frequently than females. An autoimmune pathogenesis is suggested. Symptoms comprise anterior and/or posterior pituitary insufficiency of varying degrees. So far, specific characteristics of this rare disease in childhood are not well described. Case history We report the case of a 12-year-and-11-month-old boy with histologically confirmed LYH clinically presenting with diabetes insipidus. A high-dose steroid therapy was administered, in which the therapeutic effect was uncertain. His 6-year follow-up is presented. Discussion The literature is reviewed for children presenting with LYH; their characteristics, pituitary involvement, and clinical follow-up are listed and discussed. Conclusion Even though magnetic resonance imaging can be highly suspicious for LYH, only surgical exploration can confirm the diagnosis. The efficacy of medical treatment is still controversial; a close follow-up is necessary to control and correct the endocrinological function, if required.