Clinicopathological features and prognosis assessment of extranodal follicular dendritic cell sarcoma

Table 3 Histological features of low- and high-grade FDC sarcomas

Parameters	Low-grade phenotypes	High-grade phenotypes
Architectures	Nodular patterns in whorl, storiform and fascicular arrangement	Diffuse and sheet-like patterns
Cellular features	Spindle or blunt cells with mild nuclear atypia and a small nucleolus in > 90% of area	Epithelioid or pleomorphic cells with marked nuclear atypia and large nucleoli
Mitotic counts	< 5/10 HPF	≥ 5/10 HPF
Ki-67-LI	< 10%	≥ 10%
Necrosis	Absent	Frequently present
Lymphocyte infiltration	Sporadic and throughout the lesion	Focal or regional