Angiosarcoma in an Arteriovenous Fistula Following Renal Transplantation: A Case Report and Literature Review.

Angiosarcoma is a rare and aggressive malignant tumor arising from vascular or lymphatic endothelial cells. Angiosarcoma at an arteriovenous fistula site is exceptionally rare. We report a case of a 37-year-old male renal transplant recipient who developed a high-grade epithelioid angiosarcoma at the site of an arteriovenous fistula six years post-transplant. The lesion presented as a bleeding, enlarging mass and was initially misdiagnosed, delaying definitive treatment. A biopsy confirmed the diagnosis, and the patient underwent radical surgery, chemotherapy, and radiotherapy. This case highlights the need for heightened clinical suspicion, particularly in patients with arteriovenous fistula-related complications, as early diagnosis and treatment are crucial for this rare but aggressive malignancy.