Labyrinthine involvement in Langerhans' cell histiocytosis

Background: Langerhans' cell histiocytosis, a rare condition caused by the proliferation of abnormal Langerhans' cells ('LCH cells') and an accompanyi ng granulomatous infiltrate, can affect several organs including the ear. E xternal and middle ear involvement are common with a reported incidence as high as 61%. The bony labyrinth is resistant to erosion by the granulation tissue, thereby protecting the cochlea and vestibular structures. Probably for this reason, involvement of the inner ear is rare, with few case report s in the literature. Patients: We report two girls, one with bilateral and the other with unilateral mastoid involvement, in whom there was invasion o f the labyrinth. The first girl had 'single system' LCH affecting only bone and developed an acute hearing loss due to invasion of the cochlea, while the second had both bone and skin involvement and labyrinthine involvement was diagnosed on imaging prior to the onset of labyrinthine symptoms. Concl usion : Inner ear involvement can lead to permanent deafness, which may be prevented by early institution of treatment. Threatened inner ear involveme nt requires urgent systemic medical therapy with steroids, possibly combine d with chemotherapy. (C) 1998 Published by Elsevier Science Ireland Ltd. Al l rights reserved.