Life-Threatening Lower GI Bleeding From Sigmoid Colon Metastasis of Cutaneous Angiosarcoma: A Case Report.

Angiosarcoma is a rare and aggressive malignancy of vascular endothelial origin, characterized by rapid progression and early metastatic dissemination. GI involvement is uncommon, and colonic metastasis from a cutaneous primary is exceptionally rare. We report the case of an 85-year-old man with a history of cutaneous angiosarcoma of the right cheek who presented with recurrent rectal bleeding and transfusion-dependent anemia. Colonoscopy demonstrated a large, ulcerated lesion in the sigmoid colon, causing luminal narrowing and active hemorrhage. Preoperative fluorodeoxyglucose PET-CT demonstrated focal thickening of the sigmoid colon with mild metabolic uptake, as well as increased uptake within the left pleura, raising suspicion for metastatic disease. Histopathological examination of the sigmoid lesion confirmed metastatic angiosarcoma. In the setting of ongoing bleeding and hemodynamic compromise, the patient underwent an urgent Hartmann's procedure, which achieved definitive hemorrhage control. The postoperative course was uncomplicated, with significant clinical improvement. Despite the typically aggressive behavior associated with angiosarcoma, the patient remains clinically well nearly two years following resection. This case highlights the rare occurrence of colonic metastasis from cutaneous angiosarcoma presenting as life-threatening lower GI bleeding and underscores the role of surgical resection in achieving effective hemorrhage control and meaningful clinical outcomes in selected patients.