RESUMEN
An autopsy of a 70-year-old man with multiple bone metastases from a malignancy of unknown origin (MUO) and renovascular hypertension revealed an aortic intimal sarcoma (AIS) in the right renal artery accompanied by atherosclerotic changes. AIS appeared as aggregated mutton fat-like translucent particles arising from the intima of the branching portion of the right renal artery and was composed of undifferentiated, fine spindle cells with thicket-like proliferation. AIS was confirmed by immunohistopathology, showing the loss of the lumen lined by CD31-positive endothelium and the expression of CD31, keratin, and vimentin in the viable part of the tumor. In patients with MUO presenting with both bone metastases and an acute or sub-acute onset of renovascular hypertension, AIS in the renal artery may be responsible.
