Background: Cystosarcomaphyllodes is an uncommon fibroepithelial breast neoplasm that accounts for 0.5%-1.0% of female breast carcinomas. Most affected women are between 35 to 60 years old. The proportion of duodenal metastases from breast carcinoma has been reported in autopsy series as occuring in more than 15% patients.However, gastrointestinal metastases from phyllode tumor of breast have rarely been reported in the literature. Case presentation: A 57-year-old woman presented to our emergency department in March 2023 with complaints of pain abdomen, nausea, vomiting, postprandial epigastric fullness, and discomfort that had started 1 week earlier and progressively got worse. Her symptoms were exacerbated with both solid and liquid food. e patient underwent Explorative laparotomy and intraoperative findings were suggestive of jejunal intussusception with a firm jejunal mass of 2x3 cm, and the small bowel mass with intussusception was resected with primary anastomosis. The surgical pathology revealed a grey-tan mass of 2.5x 2cm with features of a mesenchymal tumor reaching up to the submucosa with no lymph nodal dissection done . There was previous history of lumpectomy of the breast lump from which the IHC was done in May 2023 which revealed a malignant phylloids.Then the patient was advised PET-CT scan in June 2023 which showed metabolic uptake in the colon, brain, bone, and lymph nodes suggestive of metastatic disease and then she was given 30Gy/10 # WBRT in view of brain metswef 24/6/2023 till 7/7/2023 and later she was prescribed tab pazopanib. Conclusion: Cystosarcomaphyllodes is an uncommon fibroepithelial breast neoplasm and it tend to metastasize to locations such as the lung, bone, heart, and liver and rarely to small intestine . The treatment of choice for phyllodes tumors is wide surgical excision as there is no available clinical trial data for adjuvant treatment of malignant phyllodes tumors.