Abstract
BACKGROUND: Histiocytic sarcoma (HS) is a rare disease characterized by the presence of neoplastic histiocytes. We herein report an unusual case of HS that caused massive tumor embolism-related transmural necrosis of the small intestine. CASE PRESENTATION: A 64-year-old man presented with multiple nodules in the lungs, bone, mediastinum, and subcutaneous tissues that were incidentally detected on preoperative computed tomography for early transverse colon cancer. Approximately two months later, the patient presented with signs of peritoneal irritation suggestive of small intestinal necrosis. Emergency surgery was performed and the necrotic small intestine was resected. Pathological examination revealed small bowel necrosis due to multifocal HS embolism. The postoperative course was uneventful. The patient was unsuccessfully treated with chemotherapy for HS and died 122 days postoperatively. CONCLUSIONS: HS can cause massive enteric necrosis due to tumor embolism. Clinicians should be aware of this rare presentation of HS.