Histiocytic Sarcoma Treated With Autologous Stem Cell Transplantation: A Case Report and Literature Review of the Role of Autologous and Allogenic Stem Cell Transplantation.

BACKGROUND Histiocytic sarcoma is a rare and aggressive hematopoietic malignancy, characterized by tumor cells exhibiting features of histiocytes or dendritic cells. Extranodal involvement, particularly in the gastrointestinal tract, skin, and soft tissues, is common and often associated with aggressive clinical behavior and poor outcomes. Due to its rarity, no standardized treatment has been established. Current therapeutic approaches are generally adapted from aggressive non-Hodgkin lymphoma protocols, typically involving multi-agent chemotherapy. However, therapeutic responses are often suboptimal, with frequent relapses. In selected cases, hematopoietic stem cell transplantation has been employed following intensive chemotherapy for disease control. CASE REPORT A 44-year-old woman presented with pancytopenia and was initially diagnosed with immune thrombocytopenia. After splenectomy for refractory disease, histopathlogic examination of spleen confirmed histiocytic sarcoma. She received 6 cycles of chemotherapy with cyclophosphamide, doxorubicin (hydroxydaunorubicin), vincristine (Oncovin), etoposide, and prednisone. Despite an initial response, the disease progressed. She underwent high-dose chemotherapy followed by autologous hematopoietic stem cell transplantation, but ultimately died due to disease relapse. CONCLUSIONS This case demonstrates the highly aggressive course and poor prognosis of histiocytic sarcoma, even after intensive chemotherapy and autologous stem cell transplanatation. Given the highly aggressive nature of histiocytic sarcoma and its generally poor prognosis, allogeneic stem cell transplantation may offer a more effective strategy for achieving long-term remission, particularly in patients with relapsed or refractory disease. Large-scale studies are needed to establish treatment guidelines for histiocytic sarcoma.