8.2.4.8Central Nervous System

•Predilection of hypothalamic-pituitary and diabetes insipidus involvement prior, during, or after the disease (see “Endocrine Organs”)

–Intracranial hypertension or pseudotumor cerebri can be a sign of isolated or multifocal LCH: diagnostic toll is MRI

–There may also be parenchymal and/or leptomeningeal involvement

–Neurodegenerative disease (NDD) occurs in a subset of patients with par- ticular risk factors, such as orbital or sphenoid bone involvement as well as diabetes insipidus. NDD commonly includes signs of cerebellar ataxia, dys- arthria, dysphagia, and emotional lability; NDD may wax and wane over the course of many years

bone marrow. Pancytopenia usually indicates disseminated disease and may be associated with hemophagocytic syndrome (HLH)

8.2.4.10 Immune System

•No single characteristic abnormality of the immune system has been documented in patients with LCH

•Occasionally autoimmune phenomena

•Production of antired blood cell antibodies

•Decreased numbers of suppressor T-lymphocytes

•Thymus may be enlarged because of involvement with LCH; resemblance of immune deficiency with low levels of serum immunoglobulins, altered cellular immune response, and increased susceptibility to infections may be observed

8.2.4.11 Gastrointestinal Tract

•Malabsorption syndrome – Symptoms: Vomiting, diarrhea, hematochezia

•Protein-losing enteropathy (protein-loss syndrome)

Clinical manifestations of LCH (in order of frequency)