Metastatic Phyllodes Tumor Causing Small-Bowel Obstruction

Abstract Cystosarcoma phyllodes is an important but relatively uncommon fibroepithelial breast neoplasm that accounts for 0.5%–1.0% of female breast carcinomas. Malignant forms comprise nearly 25% of cases. These usually metastasize to the lung, pleura, bone, and liver. Metastases to the small intestine are extremely rare, with only 1 case of metastatic spread to the duodenum reported in the literature. No previous reports of metastatic spread to the ileum have been published. This report highlights a unique case of a metastatic phyllodes breast tumor leading to small bowel obstruction. Phyllodes tumorsare generally classified into histologic subtypes of benign, intermediate, and malignant, using agreed classification systems. The tumor characteristics that can lead to the dedifferentiation of a relatively benign phenotype to an overt malignant process are discussed. Chemotherapeutic regimens that might be effective treatments are discussed, and the importance of regular clinical and radiologic follow-up in patients with poor prognostic factors is outlined.