65 yrs old male: submandibular node was biopsied in stomatology dept. with suspition of hematological disease (fever).
HISTO:Hyperplastic II follicles with attenuated mantle zones and expanded T zone with HEVs and admixture of B immunoblasts. Cytological atypia is minimal.
IH 1: Ki67 up to 40% (interfollicular); No T Ags lost. CD21/CD23 slightly irregular, but retained FDC network. PD1+ stronger in FC than in between. CD30+ polymorphic immunoblasts in the T zone.
IH 2 (INCIDENTAL): In CD5 stain CD5dim/Bcl2 dim+ population in the mantle zone was noted: CyclinD1+ (mantle pattern and maybe slight infiltration outside)!!!
MOLECS: IgH/IgK clear clone. TCR no definite clone (not enough sensitivity to differentiate). EBER+ grouped immunoblasts in the interfollicular space.
PROPOSAL: Early immunoblastic EBER+ angioimmunoblastic T lymphoma (pattern I)+ incident B mantle cell lymphoma (early vs MCL in situ).
Dif Dx: just MCL (mantle pattern or in situ)+ EBER+ reactive component.