Multisystem langerhans cell histiocytosis with advanced orbital involvement: case report.

Langerhans cell histiocytosis (LCH) is a rare disease occurring most frequently in infancy or early childhood. The aetiology is still not completely understood, although some form of immunologic dysfunction has been implicated. Clinically, the disease may either be localised or present with multisystem involvement. Here we discuss the case of a seven year old boy presenting with advanced proptosis. To the best of our knowledge, proptosis of this extent has not been reported previously in association with LCH.