Hand-Schüller-Christian disease (alternative eponyms,Christian’s syndrome, Christian-Schüller disease, Hand’s disease, Hand-Rowland disease/syndrome, Schüller’s disease, Schüller-Christian syndrome, Schüller-Christian-Hand disease) is associated with multifocal Langerhans cell histiocytosis.
It is associated with a triad of exophthalmos, lytic bone lesions (often in the skull), and diabetes insipidus (from pituitary stalk infiltration).
It's a  rare disease of unknown cause in which lipids accumulate in the body and manifest as histiocytic granuloma in bone, particularly in the skull; the skin; and viscera, often with hepatosplenomegaly and lymphadenopathy. Exophthalmos and diabetes insipidus may be present. Both sexes affected, with a slight male predominance. The disease is seen in children and young adults, seldom in elderly persons. Onset usually before the age of six years. As originally described, this syndrome included the classic triad of unilateral or bilateral exophthalmos, diabetes insipidus, and defects in the membranous bones of the skull. Clinical features may also include defects in the mandible, long bones, pelvis, ribs, and spine.

In Letterer-Siwe disease the lesions are widespread, the disease is severe and death likely within a short time. Aetiology unknown.

First described 1891/1893 by Alfred Hand who, however, had misinterpreted the autopsy findings as tuberculosis. Arthur Schüller described the skull resembling a map – Landkartenschädel - in 1915. Henry Asbury Christian in 1920 completed the clinical picture particularly referring to the trias emphasised by Hand. The changes of the skull were first described by Sir Thomas Smith (1833-1909) in 1865.