Inflammatory pseudotumor-like follicular dendritic cell sarcoma: A brief report of two cases

Figure 4 Epstein-Barr virus positive inflammatory pseudotumor-like follicular dendritic cell sarcoma in the liver with hepatoduodenal ligament lymph node involvement. A: Gross picture of an inflammatory pseudotumor-like follicular dendritic cell sarcoma of the liver. A large and multinodular confluent tumor was found in the liver (arrow); B: Histologic sections of follicular dendritic cell sarcoma showing an unencapsulated tumor (left) with a sharp margin from the adjacent liver parenchyma (right). The tumor tissue was arranged in whorls (× 40); C: On high-power field, the tumor was composed of oval to spindle cells with vesicular chromatin and distinct nucleoli. There was less degree of atypia. The background showed abundant lymphocytes and plasma cells (× 400); D: In the hepatoduodenal ligament lymph node, lymphoid follicles were pushed aside by tumor tissue (× 100); E: CD21 was detected on the membrane of almost all of tumor cells by immunohistochemistry (× 100); F: S100 was detected in the membrance and cytoplasm of almost all of tumor cells by immunohistochemistry (× 100); G: Epstein-Barr virus-encoded small RNA in situ hybridization demonstrated positive nuclei of the neoplastic dendritic cells (× 100); H: Ki-67 was detected in the nuclei of almost all of tumor cells (20%; × 100).