{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,22]],"date-time":"2025-12-22T16:43:14Z","timestamp":1766421794560,"version":"3.48.0"},"reference-count":27,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2025,12,22]],"date-time":"2025-12-22T00:00:00Z","timestamp":1766361600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Hematology Reports"],"abstract":"<jats:p>Background and Clinical Significance: Histiocytic sarcoma (HS) is a rare and aggressive form of malignant histiocytosis, often associated with poor prognosis. The diagnosis and management of HS are challenging due to the complexity of its pathogenesis, molecular profile, and the unclear cellular origin of histiocytic neoplasms, compounded by the limited literature on treatment strategies. Case Presentation: We report the case of a young patient with HS localized to the lymph nodes, spleen, and liver, who also presented with hemophagocytic lymphohistiocytosis (HLH) documented on bone marrow biopsy. Initial treatment with CHOEP-21 and ICE-21 chemotherapy resulted in only a partial metabolic response, as evidenced by a Fluorodeoxyglucose-Positron Emission Tomography (FDG-PET)\/CT scan. Given the aggressive nature of the disease and the presence of HLH, an allogeneic hematopoietic stem cell transplantation (HSCT) from a matched unrelated donor was performed as consolidation therapy, leading to a progressive complete response without significant toxicity. A suspected relapse at 18 months post-transplant was excluded following a mediastinal lymph node biopsy, which revealed a benign intravascular papillary endothelial hyperplasia (IPEH). Over five years post-diagnosis and more than four years after transplantation, the patient remains in complete remission with full functional recovery. Conclusions: This case highlights the diagnostic and molecular challenges of HS and demonstrates the curative potential of early allogeneic HSCT, even when only partial remission is initially achieved.<\/jats:p>","DOI":"10.3390\/hematolrep18010002","type":"journal-article","created":{"date-parts":[[2025,12,22]],"date-time":"2025-12-22T16:19:26Z","timestamp":1766420366000},"page":"2","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Durable Response in Histiocytic Sarcoma After Allogeneic Stem Cell Transplantation: A Case Report"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3084-180X","authenticated-orcid":false,"given":"Stefania","family":"Oliva","sequence":"first","affiliation":[{"name":"Division of Hematology, A.O.U. Citt\u00e0 della Salute e della Scienza di Torino, 10126 Torino, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-3762-6552","authenticated-orcid":false,"given":"Jessica","family":"Gill","sequence":"additional","affiliation":[{"name":"Division of Hematology, A.O.U. Citt\u00e0 della Salute e della Scienza di Torino, 10126 Torino, Italy"},{"name":"Department of Hematology, Santa Croce e Carle Hospital, 12100 Cuneo, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5202-2621","authenticated-orcid":false,"given":"Elia","family":"Boccellato","sequence":"additional","affiliation":[{"name":"Department of Hematology, Santa Croce e Carle Hospital, 12100 Cuneo, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Umberto","family":"Mortara","sequence":"additional","affiliation":[{"name":"Department of Scienze Mediche, Anatomia Patologica 1U, A.O.U. Citt\u00e0 della Salute e della Scienza di Torino, 10126 Torino, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Luca","family":"Molinaro","sequence":"additional","affiliation":[{"name":"Department of Scienze Mediche, Anatomia Patologica 1U, A.O.U. Citt\u00e0 della Salute e della Scienza di Torino, 10126 Torino, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Laura","family":"Godio","sequence":"additional","affiliation":[{"name":"Department of Scienze Mediche, Anatomia Patologica 1U, A.O.U. Citt\u00e0 della Salute e della Scienza di Torino, 10126 Torino, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Elena","family":"Sieni","sequence":"additional","affiliation":[{"name":"Department of Oncologia, Ematologia e TCSE, Azienda Ospedaliero Universitaria Meyer IRCCS, 50139 Firenze, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4993-0765","authenticated-orcid":false,"given":"Anna Maria","family":"Buccoliero","sequence":"additional","affiliation":[{"name":"Pathology Unit, Meyer Children\u2019s Hospital IRCCS, 50139 Florence, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Irene","family":"Dogliotti","sequence":"additional","affiliation":[{"name":"SS Trapianto Allogenico e Terapie Cellulari, SC Ematologia U Dipartimento di Oncologia, A.O.U. Citt\u00e0 della Salute e della Scienza di Torino, 10126 Torino, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5361-5613","authenticated-orcid":false,"given":"Alessandro","family":"Busca","sequence":"additional","affiliation":[{"name":"SS Trapianto Allogenico Cellule Staminali, A.O.U. Citt\u00e0 della Salute e della Scienza di Torino, 10126 Torino, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Elena","family":"Califaretti","sequence":"additional","affiliation":[{"name":"SC Medicina Nucleare, A.O.U. Citt\u00e0 della Salute e della Scienza di Torino, Presidio Molinette, 10126 Torino, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7299-6770","authenticated-orcid":false,"given":"Bruno","family":"Benedetto","sequence":"additional","affiliation":[{"name":"Division of Hematology, A.O.U. Citt\u00e0 della Salute e della Scienza di Torino, 10126 Torino, Italy"},{"name":"SS Trapianto Allogenico e Terapie Cellulari, SC Ematologia U Dipartimento di Oncologia, A.O.U. Citt\u00e0 della Salute e della Scienza di Torino, 10126 Torino, Italy"},{"name":"Department of Molecular Biotechnology and Health Sciences, University of Torino, 10124 Torino, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0860-3266","authenticated-orcid":false,"given":"Luisa","family":"Giaccone","sequence":"additional","affiliation":[{"name":"SS Trapianto Allogenico e Terapie Cellulari, SC Ematologia U Dipartimento di Oncologia, A.O.U. Citt\u00e0 della Salute e della Scienza di Torino, 10126 Torino, Italy"},{"name":"Department of Molecular Biotechnology and Health Sciences, University of Torino, 10124 Torino, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1046\/j.1365-2559.2002.01418.x","article-title":"Tumours of histiocytes and accessory dendritic cells: An immunohistochemical approach to classification from the International Lymphoma Study Group based on 61 cases","volume":"41","author":"Pileri","year":"2002","journal-title":"Histopathology"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1182\/blood-2017-10-812495","article-title":"Histiocytic sarcoma: A population-based analysis of incidence, demographic disparities, and long-term outcomes","volume":"131","author":"Kommalapati","year":"2018","journal-title":"Blood"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2465","DOI":"10.1182\/blood.2018894618","article-title":"Special Report Recommendations for the management of hemophagocytic lymphohistiocytosis in adults","volume":"133","author":"Horne","year":"2019","journal-title":"Blood"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1703","DOI":"10.1038\/s41375-022-01613-1","article-title":"The 5th edition of the World Health Organization Classification of Haematolymphoid Tumours: Myeloid and Histiocytic\/Dendritic Neoplasms","volume":"36","author":"Khoury","year":"2022","journal-title":"Leukemia"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2912","DOI":"10.1182\/blood-2005-05-2004","article-title":"Hematopoietic cell transplantation (HCT)-specific comorbidity index: A new tool for risk assessment before allogeneic HCT","volume":"106","author":"Sorror","year":"2005","journal-title":"Blood"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"4","DOI":"10.1016\/j.bbmt.2015.09.001","article-title":"International, Multicenter Standardization of Acute Graft-versus-Host Disease Clinical Data Collection: A Report from the Mount Sinai Acute GVHD International Consortium","volume":"22","author":"Harris","year":"2016","journal-title":"Biol. Blood Marrow Transplant."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1186\/1746-1596-8-167","article-title":"Intravascular papillary endothelial hyperplasia: Histomorphological and immunohistochemical features","volume":"8","author":"Akdur","year":"2013","journal-title":"Diagn. Pathol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"830","DOI":"10.1038\/s41379-018-0200-x","article-title":"Identification of diverse activating mutations of the RAS-MAPK pathway in histiocytic sarcoma","volume":"32","author":"Shanmugam","year":"2019","journal-title":"Mod. Pathol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"951","DOI":"10.3324\/haematol.2019.230375","article-title":"Genomic profiling of primary histiocytic sarcoma reveals two molecular subgroups","volume":"105","author":"Egan","year":"2020","journal-title":"Haematologica"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"521","DOI":"10.1038\/s41586-019-1012-y","article-title":"Efficacy of MEK inhibition in patients with histiocytic neoplasms","volume":"567","author":"Diamond","year":"2019","journal-title":"Nature"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"e28200","DOI":"10.1002\/pbc.28200","article-title":"Secondary histiocytic sarcoma with BRAF(V600E) mutation after T-cell acute lymphoblastic leukemia in a very young child with dramatic response to dabrafenib and trametinib","volume":"67","author":"Venkataraman","year":"2020","journal-title":"Pediatr. Blood Cancer"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"618","DOI":"10.6004\/jnccn.2022.7001","article-title":"Near Complete Response to Trametinib Treatment in Histiocytic Sarcoma Harboring a Somatic KRAS Mutation","volume":"20","author":"Hu","year":"2022","journal-title":"J. Natl. Compr. Canc. Netw."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1945","DOI":"10.1056\/NEJMc1511490","article-title":"Trametinib in histiocytic sarcoma with an activating MAP2K1 (MEK1) mutation","volume":"378","author":"Gounder","year":"2018","journal-title":"N. Engl. J. Med."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"228","DOI":"10.1007\/s12185-018-2553-9","article-title":"A case of recurrent histiocytic sarcoma with MAP2K1 pathogenic variant treated with the MEK inhibitor trametinib","volume":"109","author":"Kumamoto","year":"2019","journal-title":"Int. J. Hematol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"154","DOI":"10.1158\/2159-8290.CD-15-0913","article-title":"Diverse and Targetable Kinase Alterations Drive Histiocytic Neoplasms","volume":"6","author":"Diamond","year":"2016","journal-title":"Cancer Discov."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"136","DOI":"10.3892\/mco.2022.2569","article-title":"Application of PD - L1 blockade in refractory histiocytic sarcoma: A case report","volume":"17","author":"Imataki","year":"2022","journal-title":"Mol. Clin. Oncol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"6274","DOI":"10.1097\/MS9.0000000000001446","article-title":"Favorable outcome of a histiocytic sarcoma patient treated with immune checkpoint inhibitor: A case report","volume":"85","author":"Nguyen","year":"2023","journal-title":"Ann. Med. Surg."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"826","DOI":"10.1182\/blood.2019003886","article-title":"Nivolumab treatment of relapsed\/refractory Epstein-Barr virus\u2014Associated hemophagocytic lymphohistiocytosis in adults","volume":"135","author":"Liu","year":"2020","journal-title":"Blood"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Zhao, Y., Deng, Y., Jiang, Y., Zheng, W., Tan, Y., Yang, Z., Wang, Z., Xu, F., Cheng, Z., and Yuan, L. (2023). Case report: Targeting the PD-1 receptor and genetic mutations validated in primary histiocytic sarcoma with hemophagocytic lymphohistiocytosis. Front. Immunol., 14.","DOI":"10.3389\/fimmu.2023.1127599"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"655","DOI":"10.3109\/10428194.2012.717082","article-title":"Human leukocyte antigen-haploidentical hematopoietic stem cell transplant for a patient with histiocytic sarcoma","volume":"54","author":"Zeidan","year":"2013","journal-title":"Leuk. Lymphoma"},{"key":"ref_21","first-page":"728260","article-title":"Case Report Successful Treatment of Multifocal Histiocytic Mitoxantrone (CLAG-M)Followed by Allogeneic Hematopoietic Stem Cell Transplantation","volume":"2015","author":"Tomlin","year":"2015","journal-title":"Case Rep. Hematol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"932","DOI":"10.1002\/ajh.20913","article-title":"Thalidomide for the treatment of histiocytic sarcoma after hematopoietic stem cell transplant","volume":"82","author":"Abidi","year":"2007","journal-title":"Am. J. Hematol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"e251","DOI":"10.1200\/JCO.2010.32.6603","article-title":"Autologous hematopoietic stem-cell transplantation in combination with thalidomide as treatment for histiocytic sarcoma: A case report and review of the literature","volume":"29","author":"Gergis","year":"2011","journal-title":"J. Clin. Oncol."},{"key":"ref_24","first-page":"431","article-title":"Successful autologous bone marrow transplantation in second remission of malignant histiocytosis","volume":"5","author":"Cazin","year":"1990","journal-title":"Bone Marrow Transplant."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"576","DOI":"10.1148\/rg.2021200096","article-title":"Histiocytosis and Neoplasms of Macrophage-Dendritic Cell Lineages: Multimodality Imaging with Emphasis on PET\/CT","volume":"41","author":"Huynh","year":"2021","journal-title":"Radiographics"},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Cheon, M., Yoo, J., Kim, H.S., and Lee, M. (2023). Enhanced Computed Tomography and 18F-fluorodeoxyglucose Positron Emission Tomography\/Computed Tomography in the Uncommon Histiocytic Sarcoma of Small Intestine Arising after Gastric Large B-Cell Lymphoma. Diagnostics, 13.","DOI":"10.3390\/diagnostics13203189"},{"key":"ref_27","first-page":"123","article-title":"Salvage of relapsed malignant histiocytosis by autologous bone marrow transplant","volume":"4","author":"Berry","year":"1989","journal-title":"Bone Marrow Transplant."}],"container-title":["Hematology Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2038-8330\/18\/1\/2\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,22]],"date-time":"2025-12-22T16:39:42Z","timestamp":1766421582000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2038-8330\/18\/1\/2"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,12,22]]},"references-count":27,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2026,2]]}},"alternative-id":["hematolrep18010002"],"URL":"https:\/\/doi.org\/10.3390\/hematolrep18010002","relation":{},"ISSN":["2038-8330"],"issn-type":[{"value":"2038-8330","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,12,22]]}}}