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

Sotirios G Papageorgiou,1 Aspasia Divane,2 Maria Roumelioti,3 Christine Kottaridi,4 Anthi Bouchla,1 Alexandros Georgakopoulos,5 Fotini Ieremiadou,2 Aggeliki Daraki,2 Efthymia Bazani,1 Thomas P Thomopoulos,1 Sofia Chatziioannou,5,6 Andreas Mavrogenis,7 Panayiotis Panayiotidis,3 Ioannis G Panayiotides,4 Vasiliki Pappa,1,* Periklis G Foukas4,* 1 2nd Department of Internal Medicine and Research Unit, Hematology Unit, University General Hospital “Attikon”, Haidari, Athens, Greece; 2“LIFE CODE” Private Diagnostic Laboratory, Medical Ltd., Athens, Greece; 3 1st Department of Propaedeutic Medicine, Laikon General Hospital, National and Kapodistrian University of Athens, Athens, Greece; 4 2nd Department of Pathology, National and Kapodistrian University of Athens, Medical School, University General Hospital “Attikon”, Haidari, Athens, Greece; 5 2nd Department of Radiology, Nuclear Medicine Section, National and Kapodistrian University of Athens, University General Hospital “Attikon”, Haidari, Athens, Greece; 6Nuclear Medicine Section, Biomedical Research Foundation Academy of Athens, BRFAA, Athens, Greece; 7 1st Department of Orthopaedics, National and Kapodistrian University of Athens, School of Medicine, University General Hospital “Attikon”, Haidari, Athens, Greece*These authors contributed equally to this workCorrespondence: Sotirios G Papageorgiou 2nd Department of Internal Medicine and Research Unit, University General Hospital “Attikon”, 1 Rimini St., Haidari 12462 Athens, GreeceTel +30 210-583-2318Fax +30 210-538-2306Email sotirispapageorgiou@hotmail.comBackground: Erdheim–Chester Disease (ECD) is a clonal non-Langerhans histiocytosis, classified as a macrophage-dendritic cell neoplasm in the 2016 WHO classification. The exact cell of origin of ECD is unknown, although some limited evidence suggests that it arises from myeloid progenitors.Case Presentation: A 43-year-old patient, diagnosed with BRAFV600E mutated ECD, developed NPM1+/FLT3+ acute myeloid leukemia (AML) with wild-type BRAF, 15 months after the initial ECD diagnosis. The patient received intensive chemotherapy plus midostaurin, followed by midostaurin maintenance. Six months into maintenance, the patient remains in complete remission with low-level measurable residual disease, whereas ECD shows a sustained partial metabolic response. Molecular karyotype at several distinct timepoints, namely ECD diagnosis, AML diagnosis, and following treatment of AML, highlighted a molecular signature, indicative of a persistent, underlying clonal hematopoiesis.Conclusion: This case report suggests that ECD and AML might represent an expansion of two distinct clones in a background of clonal hematopoiesis, indicating their shared origin. Moreover, molecular karyotype might serve as a strong, inexpensive tool for revealing clonal hematopoiesis in cases of negative targeted next-generation sequencing. Finally, the moderate response of ECD to midostaurin suggests that kinase inhibition might have a potential role in ECD treatment.Keywords: Erdheim–Chester disease, acute myeloid leukemia, clonal hematopoiesis, case report, molecular karyotype, midostaurin