High-grade angiosarcoma arising from a long-standing non-functioning arteriovenous fistula in a kidney transplant recipient: a case report

Arteriovenous fistulas are frequently considered biologically quiescent after successful kidney transplantation, and their long-term management remains debated. We report the case of a 59-year-old kidney transplant recipient who presented with persistent bleeding and progressive enlargement of a long-standing, non-functioning brachiocephalic arteriovenous fistula. The patient was receiving tacrolimus, mycophenolate, and steroids, with stable graft function. Clinical evaluation initially suggested pseudoaneurysm or inflammatory changes. Due to recurrent bleeding, surgical resection was performed, and histopathological examination revealed a high-grade epithelioid angiosarcoma arising from the fistula wall. Staging studies demonstrated pulmonary metastases at the time of diagnosis. The diagnosis was established only after surgery, without prior biopsy, reflecting the nonspecific clinical presentation. Despite surgical management and oncologic assessment, the disease progressed rapidly, and the patient died shortly thereafter. Angiosarcoma arising from abandoned vascular access is an exceptionally rare but highly aggressive malignancy in transplant recipients. These findings underscore the importance of early evaluation of atypical vascular access lesions in transplant recipients, as delayed diagnosis may be associated with advanced disease and poor outcomes.