Epithelioid Variant of Angiosarcoma Associated with an Arteriovenous Fistula in the Setting of Post-Renal Transplant

Abstract

Introduction/Objective Angiosarcomas are rare malignant tumors that mimic the function and morphologic features of endothelium. They are commonly associated with prior radiation exposure, but have rarely been reported arising in synthetic graft material, congenital syndromes, or in the vicinity of an ateriovenous fistula (AVF). Herein, we report the clinical and histologic features of an epithelioid angiosarcoma arising in an AFV in the setting of post-renal transplant. Methods A 67-year-old Native American man with a cadaveric kidney transplant twelve years earlier for end-stage renal disease presented with pain at the site of his wrist AVF. The initial clinical impression was of a thrombosed fistula, and a routine AVF revision was performed. Histologic sections demonstrated an infiltrative neoplasm comprised of round, moderately pleomorphic, epithelioid cells with centrally located nuclei and prominent nucleoli, which was associated with a large thrombosed vessel. By immunohistochemistry the neoplastic cells expressed CD31 and ERG, with patchy reactivity for CD34, pan-cytokeratin, and SMA. Desmin, caldesmon, calponin, EMA, and SOX10 were negative. INI-1 was retained. A re-excision was necessary for complete margination of the lesion, and demonstrated similar histologic findings to the initial specimen. Conclusion Angiosarcoma specimens in which epithelioid appearing cells predominate are classified as epithelioid angiosarcomas, a highly aggressive variant that conveys a comparatively worse prognosis than their non-epithelioid counterparts. These classically are positive for CD31, Fli-1, Factor VIII and vimentin, with variable staining for EMA, cytokeratins, and CD34. Epithelioid angiosarcoma arising from an AVF is a rare entity, with less than 30 cases reported in the literature. The diagnosis should be considered in patients presenting with an enlarging mass, pain, or bruising near a previously quiescent AVF site. Given the aggressive nature of this disease process, there may be consideration for routine submission of AVF revision specimens for histologic evaluation.