Fibroblastic reticulum cell tumor of the orbit:A clinicopathological analysis

LI Huan; ZHANG Yutao

doi:10.3969/j.issn.1007-8096.2025.11.1486

Abstract：Objective To explore the clinicopathological features,diagnosis and differential diagnosis of fibroblastic reticular cell tumor(FRCT).Methods A case of orbital FRCT was retrospectively analyzed and relevant literature was reviewed.Results The patient underwent resection and biopsy of a right orbital mass.Microscopically,the mass showed nodular growth,with spindle tumor cells arranged in bundles,whorls and storiform patterns.A few small lymphocytes were seen infiltrating between the spindle tumor cells,and scattered lymphoid follicular structures were present in some areas.The boundaries of the spindle tumor cells were unclear,and the cytoplasm was pale eosinophilic.The short spindle or oval vacuolated nuclei showed mild atypia,with smooth or slightly irregular nuclear membranes.Small nucleoli were seen in some nuclei,but mitosis was rare.The spindle tumor cells were positive for CD68,Bcl-2,and Bcl-6,partially positive for S100 and EMA,and weakly positive for Desmin;while PCK,LCA,CD1α,CD3,CD5,CD10,CD20,CD21,CD23,CD35,CD79α,Caldesmon,C-myc,CyclinD1,D2-40,and SMA were all negative.The positive rate of Ki-67 was approximately 5%.Conclusion FRCT is a rare low-grade malignant tumor of fibroblastic reticular cell origin,mostly occurring in lymph nodes,and is extremely rare in the orbit.The pathological diagnosis mainly relies on histomorphology and immunophenotype,and it needs to be differentiated from many other tumors.