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Case 201 - Discussion

Uploaded: 2011-09-22, Updated: 2011-09-22

 

T-cell prolymphocytic leukemia

  • Peripheral blood:

    • High WBC count, most cases > 100 109/L

    • Common variant: intermediate-sized lymphocyte, high N/C ratio, round or irregular nuclear contour, moderately condensed chromatin, prominent central nucleoli, deeply basophilic cytoplasm with protrusions, no granules

    • Small cell variant: small lymphocyte with round to mildly irregular nucleus, clumped chromatin with inconspicuous nucleolus, scant basophilic cytoplasm

  • Immunophenotype

    • CD2+, CD3+, CD5+, strongly CD7+, TCRαβ

    • CD4+/CD8− (60%), CD4+/CD8+ (15-25%), CD4−/CD8+ (10-15%)

    • TCL1+, CD26+, CD52+

    • Negative: NK-associated marker (CD16, CD56, CD57), and cytotoxic granule molecule (TIA-1, granzyme B)

  • Genetics

    • TCRβ, TCRγ genes rearranged

    • Rearrangement of TCL1, TCL1β in inv(14)(q11;q32.1) or t(14;14)(q11;q32.1)

    • Rearrangement of MTCP1 in t(X;14)(28;q11)

    • Trisomy 8 or iso8q

    • Mutations in ATM at 11q23