84 yrs old female underwent large intestinal resection due tu v. ascendens tumor. CLIN. DGN.: "Ca coli ascendentis cT4NxM0, penetrans ad partis rectosigmatis, ilei terminale et ureteris sin.

HISTO: on the virtual slides amd photos. Underfixed, quality not optimal

IH: Pax-5(+++) 100% , CD20(+/++) 70% (low quality), CD79a/LCA(++)100% Ig kappa+ (esp. Ig inclussions)>> Ig lambda+; Ki67 95%; Bcl2(+/++) 80% , Mum1(+/++) 60%, IgM(+/++) 60% slightly > IgD+, Bcl6(++) 80% CD10(+/-)(faint, inconclussive, artefactual?) 60%, CD3(-), ALK1(-), CD138(-), CD4(-), CD56(-), CD30(-), EMA(-), EBER(-), Ig kappa CISH+ (single cells) > >> Ig lambda CISH(-).

PROPOSED DGN: B aggressive lymphoma with plasmacytoid features: B plasmablastic lymphoma with plasmacytic differentiation in c. ascendens.

SPECIAL REMARKS: 1. CD138(-); Mum1+; CD20+; IgM+; EBER(-) phenotype in extranodal HIV(-) plasmablastic lymphoma? 2. VISUAL plasmacytic differentiation more obvious, than on IH and Ig CISH? Differential with transformed MzL with plasmacytoid differentiation?

Thankyoubeeingtogether.