Erdheim Chester disease (ECD) is a rare, non-Langerhans' cell histiocytic neoplastic disorder that usually presents in patients in their fifties. ECD often presents as a multi-system macrophagic infiltration and common sites of involvement are the central nervous system, cardiovascular system, respiratory system, retroperitoneum, and skin. Extra-skeletal involvement is usually responsible for death due to secondary complications and ECD has had until recently an extremely poor prognosis (vide infra), with less than half of patients surviving three years (1). This article is protected by copyright. All rights reserved.