Background Langerhans Cell Histiocytosis (LCH) is a rare disease resulting in lesions in a variety of organs. It is classified into multisystem LCH (MS-LCH) and single system LCH (SS-LCH). MS-LCH can be a rapidly progressive disease, with significant morbidity and mortality. It is treated with systemic chemotherapy. SS-LCH has an excellent survival but significant long-term consequences may occur. There is little evidence for optimal management of SS-LCH and treatment remains variable.
Method Case note review of 71 patients treated at a tertiary centre from 1991 to 2003 with SS-LCH, evaluating treatment, response and incidence of long-term consequences.
Results 61/71 patients with SS-LCH had isolated bone disease, of whom 50 had unifocal bone disease (UBD) and 11 had multifocal bone disease (MBD). Six patients had skin disease, three had isolated pituitary disease and one had isolated parotid gland involvement. Most patients with UBD received no treatment or local treatment only for example, curettage or intralesional steroid. 36% of patients with MBD received systemic chemotherapy. Overall, for patients with bone disease there was a 92% initial response rate and a 13% reactivation rate. All patients who required additional treatment for relapse or progression of disease presented with new symptoms within 19 months of diagnosis. The overall incidence of long-term consequences in patients with bone disease was 30% (18% in UBD, 82% in MBD). No endocrine long-term consequences were seen in any patient presenting with SS-LCH of bone or skin. Only one patient with skin disease progressed to MS disease. All three patients with isolated pituitary involvement are on hormone replacement therapy.
Conclusions Following biopsy and screening for disease elsewhere, most children with UBD can be managed conservatively and, in the absence of any progression or reactivations, be discharged from follow-up after 2 years of observation. Long-term close observation is indicated for patients with MBD, skin disease and hormone deficiencies. During the time of this study there was a high incidence of long-term consequences seen in MBD, all related to the sites of the lesions. It is possible that the current approach of treating MBD with systemic chemotherapy will reduce the incidence of long-term effects.