Rare diseases of bone

Abstract

Non-Langerhans cell histiocytosis (N-LCH) summarizes a group of rare diseases with different clinical presentations, pathogenesis and morphology. These include primary cutaneous N-LCH, cutaneous N-LCH with systemic involvement, and primary extracutaneous systemic forms with occasional cutaneous involvement.The juvenile (JXG) and non-juvenile xanthogranuloma (N-JXG) family of histiocytoses are N-LCH: the JXG family consisting of the JXG (cutaneous), xanthoma disseminatum (cutaneous and systemic) and Erdheim-Chester disease (ECD; systemic); and the N-JXG family consisting of the solitary reticulohistiocytoma (cutaneous), multicentric reticulohistiocytosis (cutaneous and systemic) and Rosai-Dorfman disease (RDD; systemic).ECD is a clonal disorder from the JXG family of N-LCH; RDD is a reactive proliferative entity from the non-juvenile xanthogranuloma family of N-LCH.ECD and RDD N-LCH are rare disorders, which are difficult to diagnose, with multi-organ involvement including bone and systemic symptoms, and which respond to therapy in an unpredictable way.The key to successful therapy is accurate identification at tissue level and appropriate staging. Patients should be observed and monitored in a long-term pattern. Prognosis depends on disease extent and the organs involved; it is generally good for RDD disease and variable for ECD.Cite this article: EFORT Open Rev 2018;3:381-390. DOI: 10.1302/2058-5241.3.170047

<p>Erdheim–Chester Disease and Acute Myeloid Leukemia with Mutated <em>NPM1</em> in a Patient with Clonal Hematopoiesis: A Case Report</p>

“…1 It is characterized by tissue infiltration by foamy histiocytes with CD68+, CD163+, factor XIIIa+, and fascin+ CD1a-, and Langerin (CD207)-phenotype, as well as fibrosis and inflammation affecting multiple organs including bones, lungs, kidneys, lymph nodes, heart, and brain. 2,3 Most recently, consensus recommendations for evaluation, diagnosis, and treatment of ECD have been published. 4 Approximately 55-70% of ECD patients harbor the BRAF V600E mutation, while other activating mutations in the MAPK pathway are also demonstrated in the majority of BRAF wild-type ECD patients.…”