CASE 1: The retroperitoneal tumor consisted of pleomorphic cells arranged in nests (zellballen), broad cords and sheets. An extensive microvascular network was present. The cells had pleomorphic nuclei and abundant lightly eosinophilic, granular cytoplasm. The nuclear chromatin was vesicular and single eosinophilic nucleoli were present in many cells. No mitoses or hyaline intranuclear pseudoinclusions were identified. Extensive areas of necrosis were seen. Numerous hemosiderin laden macrophages were dispersed throughout the tumor.
CASE 2: The retroperitoneal mass (Images 1, 2, 3, 4, 5 and 6) consisted of nests (zellballen) of pleomorphic cells separated by a prominent fibrovascular stroma. A prominent microvascular network was present. The cells were highly pleomorphic with abundant granular, eosinophilic cytoplasm. The nuclei showed marked pleomorphism with vesicular to finely stippled chromatin and some eosinophilic nucleoli. Some areas showed spindling of cells. Rare mitoses were identified. Intranuclear pseudoinclusions were not found. The gastric mass (images 1, 2, 3, 4 and 5) showed similar histology. One lymph node showed subcapsular invasion with pleomorphic cells with abundant granular eosinophilic cytoplasm.