Long bone involvement is almost universal in ECD patients and is bilateral and symmetrical in nature. More than 50% of cases have some sort of extraskeletal involvement. This can include kidney, skin, brain and lung involvement, and less frequently retroorbital tissue, pituitary gland and heart involvement is observed.[3]
Bone pain is the most frequent of all symptoms associated with ECD and mainly affects the lower limbs, knees and ankles. The pain is often described as mild but permanent, and juxtaarticular in nature. Exophthalmos occurs in some patients and is usually bilateral, symmetric and painless, and in most cases it occurs several years before the final diagnosis. Recurrent pericardial effusion can be a manifestation,[4] as can morphological changes in adrenal size and infiltration.[5]
A review of 59 case studies by Veyssier-Belot et al. in 1996 reported the following symptoms in order of frequency of occurrence:[6]
Radiologic osteosclerosis and histology are the main diagnostic features. Diagnosis can often be difficult because of the rareness of ECD as well as the need to differentiate it from LCH. A diagnosis from neurological imaging may not be definitive. The presence of symmetrical cerebellar and pontine signal changes on T2-weighted images seem to be typical of ECD, however, multiple sclerosis and metabolic diseases must also be considered in the differential diagnosis.[7] ECD is not a common cause of exophthalmos but can be diagnosed by biopsy. However, like all biopsies, this may be inconclusive.[8]Video-assisted thoracoscopic surgery may be used for diagnostic confirmation and also for therapeutic relief of recurrent pericardial fluid drainage.[9]
There are two FDA-approved targeted drugs to treat ECD.
Vemurafenib, an oral agent approved in 2019, targets the BRAF protein. It was approved after showing dramatic efficacy in ECD patients harboring the BRAF V600E mutation.[10][11]
Cobimetinib, an oral inhibitor of MEK1 and MEK2, was approved in November 2022.[12]
Erdheim–Chester disease was previously associated with high mortality rates.[14] However, long-term survival is now more promising. Recent studies have reported that some patients receiving targeted therapies showed no disease progression. Targeted therapies using BRAF, MEK and/or other inhibitors have been dramatically efficacious.[10][13][15][16] In 2019, the Mayo Clinic published guidelines for the diagnosis and treatment of the disease, stressing the importance of genetic testing: "Recent insights into their genomic architecture demonstrating mitogen-activated protein kinase/extracellular signal-regulated kinase pathway mutations have now enabled potential treatment with targeted therapies in most patients."[17]
Epidemiology
Approximately 500 cases had been reported in the literature as of 2014.[18] ECD affects predominantly adults, with a mean age of 53 years.[6]
In the TV show House, season 2 episode 17, "All In", the initial and final diagnosis of a 6-year-old boy who presents with bloody diarrhea and ataxia is Erdheim–Chester disease.[23]
^Lutz SZ, Schmalzing M, Vogel-Claussen J, Adam P, May AE (September 2011). "[Recurrent pericardial effusion as first manifestation of Erdheim-Chester disease]" [Recurrent pericardial effusion as first manifestation of Erdheim-Chester disease]. Deutsche Medizinische Wochenschrift (in German). 136 (39): 1952–1956. doi:10.1055/s-0031-1286368. PMID21935854.
^Weidauer S, von Stuckrad-Barre S, Dettmann E, Zanella FE, Lanfermann H (April 2003). "Cerebral Erdheim-Chester disease: case report and review of the literature". Neuroradiology. 45 (4): 241–245. doi:10.1007/s00234-003-0950-z. PMID12687308. S2CID9513277.
^Chester W (1930). "Über Lipoidgranulomatose". Virchows Archiv für Pathologische Anatomie und Physiologie und für Klinische Medizin. 279 (2): 561–602. doi:10.1007/BF01942684. S2CID27359311.
de Abreu MR, Castro MO, Chung C, Trudell D, Biswal S, Wesselly M, Resnick D (2009). "Erdheim-Chester disease: case report with unique postmortem magnetic resonance imaging, high-resolution radiography, and pathologic correlation". Clinical Imaging. 33 (2): 150–153. doi:10.1016/j.clinimag.2008.09.009. PMID19237062.
Drier A, Haroche J, Savatovsky J, Godenèche G, Dormont D, Chiras J, et al. (May 2010). "Cerebral, facial, and orbital involvement in Erdheim-Chester disease: CT and MR imaging findings". Radiology. 255 (2): 586–594. doi:10.1148/radiol.10090320. PMID20413768.
Haroche J, Amoura Z, Dion E, Wechsler B, Costedoat-Chalumeau N, Cacoub P, et al. (November 2004). "Cardiovascular involvement, an overlooked feature of Erdheim-Chester disease: report of 6 new cases and a literature review". Medicine. 83 (6): 371–392. doi:10.1097/01.md.0000145368.17934.91. PMID15525849. S2CID1426013.
Haroche J, Amoura Z, Trad SG, Wechsler B, Cluzel P, Grenier PA, Piette JC (October 2006). "Variability in the efficacy of interferon-alpha in Erdheim-Chester disease by patient and site of involvement: results in eight patients". Arthritis and Rheumatism. 54 (10): 3330–3336. doi:10.1002/art.22165. PMID17009306.
Lachenal F, Cotton F, Desmurs-Clavel H, Haroche J, Taillia H, Magy N, et al. (October 2006). "Neurological manifestations and neuroradiological presentation of Erdheim-Chester disease: report of 6 cases and systematic review of the literature". Journal of Neurology. 253 (10): 1267–1277. doi:10.1007/s00415-006-0160-9. PMID17063320. S2CID27976718.
Mossetti G, Rendina D, Numis FG, Somma P, Postiglione L, Nunziata V (2003). "Biochemical markers of bone turnover, serum levels of interleukin-6/interleukin-6 soluble receptor and bisphosphonate treatment in Erdheim-Chester disease". Clinical and Experimental Rheumatology. 21 (2): 232–236. PMID12747282.
Perlat A, Decaux O, Sébillot M, Grosbois B, Desfourneaux V, Meadeb J (May 2009). "Erdheim-Chester disease with predominant mesenteric localization: lack of efficacy of interferon alpha". Joint Bone Spine. 76 (3): 315–317. doi:10.1016/j.jbspin.2008.09.013. PMID19119043.