Consensus criteria for diagnosis, staging, and treatment response assessment of T-cell prolymphocytic leukemia

Abstract

T-cell prolymphocytic leukemia (T-PLL) is a rare, mature T-cell neoplasm with a heterogeneous clinical course. With the advent of novel treatment options that will potentially change the management of patients with T-PLL, it has become necessary to produce consensus guidelines for the design and conduct of clinical trials. The T-PLL International Study group (TPLL-ISG) set out to define standardized criteria for diagnosis, treatment indication, and evaluation of response. These criteria will facilitate comparison of results from clinical trials in T-PLL, and will thus support clinical decision making, as well as the approval of new therapeutics by healthcare authorities.

Figure 1.

Microscopy of T-cell prolymphocytic leukemia. (A) Peripheral blood smear showing 2 medium-sized atypical lymphocytes with round nuclei and prominent nucleoli and abundant basophilic cytoplasms without granules. (B) Cutaneous involvement in T-PLL. Dense dermal infiltrates with marked epidermotropism simulating mycosis fungoides. (C) Bone marrow infiltration by T-PLL with an interstitial infiltration pattern depicted by an immunohistologic stain with an antibody against TCL1. (D) T-cell origin of TCL-1⁺ cells confirmed by immunohistology by double staining with CD5 (red) and TCL1 (brown).

Figure 2.

Immunophenotypic markers of T-PLL and typical chromosome banding analysis. (A) Flow cytometry of CD3⁺, CD5⁺, cytoplasmic TCL1⁺ T-PLL cells. (B) Two representative T-PLL chromosome banding analyses.