Diabetes insipidus caused by extramedullary hematopoiesis.

Myeloid metaplasia involving the central nervous system is a rare occurrence most frequently found as an incidental finding at autopsy. A case is presented of a 56-year-old man with myeloid metaplasia and myelofibrosis, who developed diabetes insipidus. Postmortem examination revealed posterior pituitary involvement by extramedullary hematopoiesis with fibrosis and gliosis. Diabetes insipidus caused by extramedullary hematopoiesis is a rare event and is thus noteworthy.