Neoplastic T-cell Processes_Fellowship

• 1) Adult T-cell Leukemia - CD7 neg w/ strong CD25
• 2) Peripheral T NOS - CD5 or CD7 neg
• 3) ALCL/ALK+ = CD3 neg, often CD5 and CD7 neg, usually CD43+, strong CD25+
• 4) ALCL/ALK- = CD3 neg, often lose T-cell marker
• 4) MF/Sezary = loss CD7 or diminished CD2, CD5, or sometimes CD3

• T cells: CD4+, CD10, BCL6 with no loss pan-T markers, PD-1, CD10, CXCL13
• FDM: disorganized & surrounds HEV

EBV-driven large, often multinucleated R-S like cells as well as immunoblasts scattered throughout small to medium malignant T-cells with clear cytoplasm with minimal nuclear atypia

BCL2

Peripheral T NOS Enteropathy associatedT-cell with gamma/delta, CD56+, CD3+ALK+ ALCL (rare!)

• Type I: CD3+, CD4-, CD8-, CD56-, CD103+, TCRbeta/gamma+, subset CD30+ in most cases
• Type II (monomorphic): CD3+, CD4-, CD8+, CD56+, TCRbeta/gamma+
• Type I - Gain 1q or 5q; Type II - MYC amplifications (8q24)

Blastic mantle cell, atypical CLL, and B-PLL (very rare!); 1) 80%  inversion chrom 14 w/ brkpts @ q11 and q32,  2) 70-80% chromosome 8 abnormalities: idic 8p11, t(8;8)(p11-12;q12); TCRγ&β rearranged

• HSM w/rash in 20% of cases, anemia, thrombocytopenia, ↑↑↑WBC (>100k
• with 50% of cases >200k), minority show serous effusions, esp pleural; small-med lymphoid cells with irregular nuclear contours, prominent nucleolus; 25% co-express CD4+/CD8+ (but usually CD4+/CD8-)

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