Clinicopathological and molecular features of Erdheim-Chester disease accompanied with Langerhans cell histiocytosis

Abstract

Objective: To investigate the clinicpathological and molecular features of Erdheim-Chester disease (ECD) as well langerhans cell histiocytosis (LCH). Methods: The clinical, histopathological, molecular findings, immunophenotype, treatment and prognosis in 4 cases of ECD combined LCH were evaluated from February 2015 to September 2018 with review of the relevant literature. Results: 2 cases were male, and 2 were female, aged from 7-55 years. Microscopically, there were two different areas, in the first area, the lesions were composed of foamy histiocytes, spindle-shaped fibroblasts, scattered multinucleated giant cells. Lymphocytes, plasma cells, and giant cells were also found. In the other, the lesions were composed of histiocytes with obvious nuclear groove, associated with a variable number of eosinophils, lymphocytes and plasma cells. Immunephenotype, In the second area, histiocytes were positive for CD1a (4/4), S-100 (4/4),CD207/Langerin (4/4), cyclin D1(4/4), and in the two different area, the histiocytes were positive for CD68, CD163, Braf. Ki-67 positive index 1%-10% BRAF V600E gene mutation was detected in three cases. Conclusion: ECD combined LCH was a very rare histiocytosis tumor and its correct diagnosis relies on histopathologic features, immunohistochemical staining, and BRAF V600E gene detection.