Abstract
BACKGROUND: Undifferentiated pleomorphic sarcoma (UPS), also known as malignant fibrous histiocytoma (MFH), hardly originates from the colorectum. CASE PRESENTATION: We reported a 65-year-old female presented with UPS in the descending colon. Computed tomography (CT) revealed an irregularly thickened descending colon. On colonoscopy examination, an ulcerative tumour was identified. The patient received radical resection of the left colon and partial enterectomy. The resected tumor was ulcerative, 10 cm × 8 cm × 5 cm in size, and infiltrated the serosa layer. Postsurgical pathology showed that the tumor was high-graded UPS in the colon with large amounts of necrotic tissues. CONCLUSIONS: UPS in the large intestine is a rare malignant tumor with a poor prognosis and unknown pathogenesis. The main treatment for UPS is early complete resection. Postsurgery adjuvant radiotherapy or chemotherapy can be attempted.