Central nervous system involvement
These lesions are most frequently observed in the hypothalamic-pituitary region. The tumor size ranges from discrete thickening of the pituitary stalk to larger tumors. Parenchymal, meningeal or choroid plexus lesions occur less frequently [Grois et al 2010].
In addition to hormone replacement isolated cerebral tumors should be treated with irradiation or chemotherapy and pituitary/hypothalamic lesions with chemotherapy. Multifocal brain lesions or single brain lesions with multi system disease need to be treated with chemotherapy. The most suitable drugs are Cladribine or Cytarabine as described above. (Grade C2 *)
Non-tumorous MRI findings of the cerebellum, and/or brain stem are histopathologically different than the typical LCH mass lesions. The neurodegenerative lesions lack CD1a+ histiocytes and have infiltrating CD8+ lymphocytes. [Grois et al 2005]. Some of these patients show no symptoms, others have clinical signs ranging from subtile tremor, dysarthria, dysphagia, and motor spasticity to pronounced ataxia, behavioral disturbances and severe psychiatric disease.
Retinoic acid and intravenous immunoglobulin may stabilize such patients [Idbaih et al 2004; Imashuku et al 2008]. Improvement with infliximab has been observed in one case [Chohan et al 2012]. Cytarabine with or without Vincristine provided improvement in 5/8 patients of which 4/8 remained stable over more than 7 years of follow-up and one relapsed but is improved after treatment with intravenous Methotrexated. Patients who responded to Cytarabine/Vincristine had symptoms for less than 18 months before starting treatment [Allen et al 2010; Allen 2010]. Thus early onset of Cytarabine is recommended as first line therapy, but for any case of neurodegenerative LCH we suggest discussion with the reference centre for your country. (Grade C1*)
* Grades of recommendation see here.