Figure 1

Selected images from the pathological evaluation. (A) The retroperitoneal mass is composed of cellular fusiform cells with a staghorn vascular pattern. Mitotic figures are frequent, but no atypical forms are seen (hematoxylin and eosin stain 10×). (B) An immunohistochemical stain for CD34 performed on the retroperitoneal mass (10×). (C) A core biopsy of the liver shows increased cellularity and increased cellular pleomorphism, with areas of necrosis (hematoxylin and eosin stain 10×). (D) An immunohistochemical stain for CD34 performed on liver mass (10×).