True T-cell chronic lymphocytic leukemia: a morphologic and immunophenotypic study of 25 cases [see comments]

Abstract

We studied 25 T-cell chronic lymphocytic leukemia (T-CLL) cases collected over a 15-year period. Immunophenotypic analysis was performed in each case; 12 cases were evaluated by cytogenetics, and gene rearrangement studies were performed in 14 cases. The median age was 57 years with a male predominance (M:F, 15:10). The median presenting lymphocyte count was 36.3 x 10(9)/L (range, 3.9 to 438 x 10(9)/L). Fourteen patients (56%) had shotty adenopathy and ten (40%) had mild-to-moderate splenomegaly at presentation; four (16%) had erythematous skin lesions. The lymphocytes were predominantly small; some cases had a minor component of medium-sized cells (< 10%). The nuclear: cytoplasmic ratios were uniformly high with round to oval nuclei; however, a wide spectrum of nuclear outlines could be found, ranging from minimally to markedly convoluted. Nucleoli were either absent or small and inconspicuous. These lymphocytes did not have the morphology of prolymphocytes and did not contain cytoplasmic granules. Bone marrow infiltration was generally in an interstitial pattern; the degree of involvement ranged from 15% to 90%. Immunophenotyping showed that the lymphocytes were mature T-cells with a predominant CD4+ immunophenotype. Three cases displayed a CD8+ immunophenotype. The patients were treated with a variety of chemotherapeutic regimens with only a minimal response observed in two of 20 patients. We conclude that T-CLL is an uncommon chronic lymphoproliferative disorder (CLPD) that can be morphologically similar to B-CLL, is distinct from T- prolymphocytic leukemia, and has an aggressive clinical course that is refractory to therapy. It may also be difficult to distinguish T-CLL from other T-CLPD, especially the leukemic phase of peripheral T-cell lymphoma and some cases of Sezary syndrome.

Indolent course as a relatively frequent presentation in T‐prolymphocytic leukaemia

“…T-cell prolymphocytic leukaemia (T-PLL) is a rare mature T-cell disorder. It is usually characterized by an aggressive clinical course with lymphadenopathy, splenomegaly, skin lesions, rapidly increasing lymphocytosis, and poor response to chemotherapy (Matutes et al, 1991;Hoyer et al, 1995).…”

“…T-PLL is also called T-cell chronic lymphocytic leukaemia (T-CLL) because of the mature aspect of the proliferating cells (Naeme et al, 1993;Hoyer et al, 1995;Hanson et al, 1996;Wong et al, 1996). However, several features frequently observed in T-PLL distinguish it from true CLL, i.e.…”

U.S.‐Canadian consensus recommendations on the immunophenotypic analysis of hematologic neoplasia by flow cytometry: Medical indications

“…The lack of expression of certain antigens, such as CD10, CD22, CD103, and FMC-7, is also characteristic and helpful in distinguishing CLL from other forms of CLPD (58,73,95). Furthermore, FCM can more easily distinguish CLL from other morphologically similar CLPDs, which might necessitate different clinical management, such as those of T-cell lineage (60).…”

“…The T-cell chronic lymphoproliferative disorders are relatively uncommon and account for Ͻ5% of CLPD (60). The most commonly encountered T-cell disorders are the so-called large granular lymphocyte (LGL) leukemias (86,133).…”

“…A T-cell form of PLL is a well-accepted entity (90). However, the existence of a true T-cell form of CLL appears to be so uncommon (60), to have some question the validity of such a distinct entity (91).…”