Presentation of LCH in Children
Patients with diabetes insipidus have a 50% to 80% chance of developing other lesions diagnostic of LCH within 1 year of identifying diabetes insipidus. A study of 589 patients with LCH revealed the 10-year risk of pituitary involvement was 24%. These investigators did not see a decreased incidence of diabetes insipidus in chemotherapy-treated patients, but this may reflect the length of the therapy and/or the number of drugs used. Using longer therapy and more drugs, the German-Austrian-Dutch (Deutsche Arbeits-gemeinschaft für Leukaemieforschung und-therapie im Kindesalter [DAL]) Group and the Japanese Langerhans Cell Group found the cumulative incidence to be 12%.[30,31] Diabetes insipidus followed initial LCH diagnosis by a mean of 1 year and growth hormone deficiency occurred 5 years later.
Patients with multisystem disease and craniofacial involvement at the time of diagnosis, particularly of the orbit, mastoid, and temporal bones, carried a significantly increased risk of developing diabetes insipidus during their course (relative risk, 4.6), with 75% of patients with diabetes insipidus having these CNS-risk bone lesions. This risk increased when the disease remained active for a longer period of time or reactivated. The risk for development of diabetes insipidus in this population was 20% at 15 years after diagnosis. The incidence of diabetes insipidus was lower in patients treated with more intensive chemotherapy regimens on the JLSG-96 and JLSG-02 studies in Japan (8.9% for multisystem patients) than on the LCH-I and LCH-II studies (14.2%).[31,32,33] Fifty-six percent of diabetes insipidus patients will develop anterior pituitary hormone deficiencies (growth, thyroid, or gonadal-stimulating hormones) within 10 years of the onset of diabetes insipidus. Diabetes insipidus occurs in 11% of patients treated with multiagent chemotherapy and in up to 50% of patients treated less aggressively.[34,35]
Central nervous system
CNS disease manifestations
LCH patients may develop mass lesions in the hypothalamic-pituitary region, the choroid plexus, the grey matter, or the white matter. These lesions contain CD1a-positive LCH cells and CD8-positive lymphocytes, and are, therefore, active LCH lesions.
Patients with large pituitary tumors (>6.5 mm) have a high risk of anterior pituitary dysfunction and neurodegenerative CNS LCH. A retrospective study of 22 patients found that all had radiologic signs of neurodegenerative CNS LCH detected at a median time of 3 years and 4 months after LCH diagnosis and that it worsened in 19 patients. Five had neurologic dysfunction. Eighteen of 22 patients had anterior pituitary dysfunction and 20 had diabetes insipidus. Growth hormone deficiency occurred in 21 patients; luteinizing hormone/follicle-stimulating hormone deficiency occurred in ten patients; and thyroid hormone deficiency occurred in ten patients.