The reported overall incidence of long-term consequences of Langerhans cell histiocytosis (LCH) has ranged from 20% to 70%. The reason for this wide variation is due to case definition, sample size, therapy used, method of data collection, and follow-up duration. Of note, in one study of the quality of life of long-term survivors of skeletal LCH, the quality of life scores were not significantly different from healthy control children and adults. In addition, the quality of life scores were very similar between those with and without permanent sequelae. In another study of 40 patients who were carefully screened for late effects, adverse quality-of-life scores were found in more than 50% of patients. Seventy-five percent of patients had detectable long-term sequelae—hypothalamic/pituitary dysfunction (50%), cognitive dysfunction (20%), and cerebellar involvement (17.5%) being the most common.
Children with low-risk organ involvement (skin, bones, lymph nodes, or pituitary gland) have an approximately 20% chance of developing long-term sequelae. Those with diabetes insipidus are at risk for panhypopituitarism and should be monitored carefully for adequacy of growth and development. In a retrospective review of 141 patients with LCH and diabetes insipidus, 43% developed growth hormone (GH) deficiency. [4,5,6] The 5-year and 10-year risks of GH deficiency among children with LCH and diabetes insipidus were 35% and 54%, respectively. There was no increased reactivation of LCH in patients who received GH compared with those who did not.
Growth and development problems are more frequent because of the young age at presentation, and the more toxic effects of long-term prednisone therapy in the very young child. Patients with multisystem involvement have a 71% incidence of long-term problems.[3,4,5,6]
Hearing loss has been found in 38% of children treated for LCH. Seventy percent of LCH patients in this study had ear involvement which included aural discharge, mastoid swelling, and hearing loss. Of those with computed tomography or magnetic resonance imaging (MRI) abnormalities in the mastoid, 59% had hearing loss.[Level of evidence: 3iiiC]
Neurologic symptoms secondary to vertebral compression of cervical lesions have been reported in 3 out of 26 LCH patients with spinal lesions. Central nervous system (CNS) LCH occurs most often in children with LCH of the pituitary or CNS-risk skull bones (mastoid, orbit, or temporal bone). Significant cognitive defects and MRI abnormalities may develop in some long-term survivors with CNS-risk skull lesions. Some patients have markedly abnormal cerebellar function and behavior abnormalities, while others have subtle deficits in short-term memory and brain stem-evoked potentials.