Extra-Nodal Follicular Dendritic Cell Sarcoma with Unusual Morphological Features and PDL1 Expression

Abstract Follicular dendritic cell (FDC) sarcoma, a rare tumor of FDCs, poses diagnostic challenge due to its myriad morphologic and architectural patterns. We present unique case extra-nodal FDC sarcoma occurring in 28-year-old gentleman who presented with multiple pelvic, peritoneal retroperitoneal soft tissue, axial skeletal lesions. The was composed islands trabeculae epithelioid cells interspersed lymphocytes against background abundant myxoid matrix. On immunohistochemistry, addition the CD21, positive for GATA3, inhibin, programmed death-ligand 1 (PDL1), which have been rarely reported previously sarcoma. patient underwent surgical excision later offered immunotherapy. He has disease-free 2 years following Our highlights potential role immune checkpoint inhibitors treating show immuno-expression PDL1.