Disseminated Histiocytic Sarcoma With Multiorgan Infiltration and Cancer Cachexia: An Autopsy Case Report

Histiocytic sarcoma (HS) is a rare and aggressive haematopoietic malignancy of mature histiocytes, with few cases reported from sub‐Saharan Africa. We report a 67‐year‐old woman who presented with progressive abdominal swelling, hepatosplenomegaly, generalised lymphadenopathy, cachexia, anaemia and thrombocytopenia. Despite supportive care, including transfusions and antibiotics, her condition rapidly worsened, and she died 9 days after admission. Autopsy revealed disseminated disease with massive splenomegaly and infarcts, hepatomegaly, generalised lymphadenopathy, pulmonary and renal involvement, and profound cancer cachexia. Histopathology demonstrated diffuse infiltration by large atypical pleomorphic histiocytic cells. Immunohistochemistry confirmed HS, with strong CD68, CD163 and CD45 expression, variable cytoplasmic CD3 positivity, and a high–Ki‐67 proliferative index, whereas excluding other lymphoid, myeloid, epithelial and plasma cell neoplasms. This case highlights the aggressive nature of disseminated HS, the clinical impact of cancer anorexia–cachexia syndrome, and the poor outcomes associated with advanced disease. It also highlights diagnostic challenges in resource‐limited settings, where limited access to immunohistochemistry contributes to under‐recognition. Broader reporting of HS from low‐ and middle‐income countries is needed to improve awareness, guide timely diagnosis and inform management strategies.