73 yrs old male with lymph node biopsy (neck). Threpine biopsy for staging: negative (not included).
HISTO: ALCL like sparse large "anaplastic" cell infiltrate with T CD4+ cytotoxic phenotype, enriched with histiocytes (?) and FDC network disruption.
IH: CD3/CD4+, TIA1+, GranzymB+, Ki67+ 80%, PD1/CD10/CD8(-), Bcl6+, EBER(-), EMA(-), CD30(-).
SPECIAL features: PTCL with ALCL like appearance (large cell variant?).
PTCL: unusual large cell variant