Langerhans Cell Histiocytosis (LCH) with Neurodegeneration, Prior to Erdheim-Chester Disease (ECD)
- Langerhans cell histiocytosis:
- Associated with several sites of involvement in children
- Classically, causes lytic bony lesions that often occur in the skull and face
- Another typical presentation is involvement of the pituitary infundibulum causing central diabetes insipidus
- Can also cause neurodegeneration
- Bilateral symmetric lesions in the dentate nucleus of the cerebellum or basal ganglia
- Symptoms: clumsiness, tremor, dysarthria, dysphagia, nystagmus, dysmetria, and ataxia
- Radiologic ND-LCH didn’t regress in this patient, up to 66% progress
- Association of Langerhans cell histiocytosis (LCH) and Erdheim-Chester disease (ECD)
- Has been reported in a series of 23 patients and 17 other case reports
- This association has been linked to BRAF V600E mutation
- ECD followed (52%) or was diagnosed simultaneously (48%) with but never preceded LCH.
- Key diagnostic features:
- Lytic skull, temporal bone or facial lesions
- Loss of neurohypophseal T1 hyperintensity and infundibular thickening in context of central DI
- Dentate nuclei and cerebellar white matter T2 hyperintensities
- DDX for multiple lytic bone lesions in child:
- Metastatic disease
- Chronic recurrent multifocal osteomyelitis
- Dermoid/epidermoid (skull)
- Leptomeningeal cyst (skull)
- DDX for loss of neurohypophyseal T1 hyperintensity and infundibular thickening:
- Germ cell tumors
- Lymphocytic hypophysitis
- Treatment: Excision/currettage for skull lesions, chemotherapy for systemic disease, vasopressin for central DI, neuropsychiatric testing to detect early symptoms of neurodegeneration
