Permanent consequences in Langerhans cell histiocytosis patients: a pilot study from the Histiocyte Society-Late Effects Study Group

BACKGROUND: Permanent consequences (PC) are often described among subjects with Langerhans cell histiocytosis (LCH) but data on the real incidence are scarce. Within the Histiocyte Society (HS), and in order to design a definitive late effects study, a retrospective survey was organized to describe the prevalence of PC among long-term survivors of LCH. METHODS: Nine institutions contributed with their LCH patients having a minimum follow-up of 3 years. Information was collected on their disease-history, and on type and date of onset of any PC. Because of the retrospective type of this study, it was accepted that each institution might have used different criteria to assess PC. RESULTS: One hundred eighty-two subjects were registered and in 95 (52%) at least 1 PC was reported. For some specific PC (e.g., anterior pituitary dysfunction) information was too scarce to provide reliable data. PC were more frequent among subjects with multisystem (MS) disease (71%), compared to those with single system (SS) disease (24%); P < 0.0001. The most frequently reported PC were diabetes insipidus (DI) (24%) orthopedic abnormalities (20%), hearing loss (13%), and neurological consequences (11.0%). Analysis of cumulative risk showed that some types of PC may become manifest more than 10 years from diagnosis. CONCLUSIONS: This survey on selected cases of LCH survivors has confirmed that late sequels are frequent, and that they are even more common among those with MS LCH. Our findings highlight the need for long-term and patient-oriented follow-up in children with LCH.