Hepatosplenic γδ T-cell lymphoma

AIM: To investigate the clinicopathologic characteristics, immunophenotype and TCR gene rearrangements of hepatosplenic T-cell lymphoma in eight Chinese patients. METHODS: Eight Chinese patients with hepatosplenic γδ T-cell lymphomas were studied. Hematoxylin-eosin-stained slides and clinical histories were reviewed. We also carried out immunohistochemical staining for CD3, CD4, CD8, CD20, CD43, CD56, CD79a, UCHL-1, and TCR γδ. Rearrangements of TCR gamma and delta chain genes were also studied. RESULTS: The spleens were enlarged and the cut surfaces were homogeneous and red-purple in color without identifiable gross lesions or enlarged hilar lymph nodes. Histologically, Iymphoma cells infiltrated the cords of Billroth and often packed the sinuses. Liver biopsy showed Iymphoma cell infiltrations in the sinusoids, and three cases showed involvements of the portal tracts. Immunohistochemically Iymphoma cells were positive for CD3, CD43, and CD56 in all cases. Four of eight cases were positive for CD8, and all cases were negative for CD4 (6/6). Monoclonal rearrangements of TCR γ gene were demonstrated by PCR analysis in five out of the eight cases. TCR δ gene rearrangements were detected in six out of the eight cases, which demonstrated single bands on PAGE gel, and the amplification products in two cases were confirmed by sequencing. CONCLUSION: The clinicopathology of hepatosplenic γδ T-cell lymphoma in Chinese patients is similar to what was previously reported except that the splenomegaly is not so massive, and CD8 is positive.     

Improvement of extrathymic T cell type of large granular lymphocyte (LGL) leukemia by cyclosporin A: the serum level of Fas ligand is a marker of LGL leukemia activity

We report a case of gammadelta T-cell-type large granular lymphocyte (LGL) leukemia (CD3 +,CD8 +, CD57 +,TCR gammadelta+), which was accompanied by pure red cell aplasia, neutropenia and thrombocytosis. Southern blotting analysis of the T-cell receptor beta gene showed the germline configuration, but clonal TCR J gamma rearrangements were identified. These granular lymphocytes demonstrated non-major histocompatibility complex-restricted cytotoxicitity. The serum-soluble FasL (sFasL) concentration of this patient was very high, whereas the serum levels of tumor necrosis factor alpha (TNF-alpha), interferon gamma (IFN-gamma), interleukin-1 beta (IL-1beta), interleukin-2 (IL-2) and thrombopoietin were normal. After treatment with cyclosporin A, anemia and thrombocytosis were improved, and LGL and the elevated sFasL concentration decreased. These observations suggested that FasL may have played a role in the establishment of the clinical symptoms of this patient and could be useful as an indicator of disease activity.     

Hepatosplenic T-cell lymphoma: a distinct clinicopathologic entity of cytotoxic gamma delta T-cell origin

We identified eight cases of T-cell lymphoma with evidence of a gamma delta phenotype over a 13-year period. Seven of these cases conformed to a distinct clinicopathologic entity of hepatosplenic gamma delta T- cell lymphoma. Nearly all of these patients were young adult males (five of seven), with a median age at presentation of 20 years. They presented with marked hepatosplenomegaly, without lymphadenopathy or significant peripheral blood lymphocytosis. Thrombocytopenia was seen in all patients, and five of seven were mildly anemic. The clinical course was aggressive, and despite multiagent chemotherapy, the median survival duration was less than 1 year. The morphologic findings were uniform; a monomorphic population of medium-sized lymphoid cells with moderately clumped chromatin and a rim of pale cytoplasm infiltrated the sinusoids of the spleen, liver, and bone marrow. The cells had a characteristic immunophenotype: CD2+, CD3+, CD4-, CD5-, CD7+, CD16+, CD57-, CD25-, T-cell receptor (TCR)delta +, beta F1-. CD8 was positive in four of seven cases tested, and CD56 was positive in five of six. All cases expressed the cytotoxic granule-associated protein, TIA1, but perforin was detected in only one case. All cases with assessable DNA had a TCR gamma gene rearrangement, and lacked Epstein-Barr virus sequences. Isochromosome 7q was identified in two cases with cytogenetic information. The one case of cutaneous gamma delta T-cell lymphoma differed in its clinical manifestations, histologic appearance, and immunophenotype. We conclude that hepatosplenic gamma delta T-cell lymphoma is a distinct clinicopathologic entity derived from cytotoxic gamma delta T cells, and should be distinguished from other lymphomas of T-cell and natural-killer cell (NK)-like T-cell derivation.     

CD20- and CD56-Positive T-Cell Large Granular Lymphocyte Leukemia in a Human T-Cell Leukemia Virus Type 1 Carrier

A 60-year-old man was diagnosed with asymptomatic T-cell granular lymphocyte (T-LGL) leukemia in September 2006. He was serologically positive for human T-cell leukemia virus type 1 (HTLV-1). However, monoclonal integration of the HTLV-1 genome was not detected in the peripheral blood, suggesting that HTLV-1 did not contribute to the pathogenesis of T-LGL leukemia in the present case. Phenotypically, neoplastic cells of our case were CD3+, CD4*, CD8+, CD16-, CD56+, CD57*, and T-cell receptor (TCR) alphabeta+. They also coexpressed CD20 antigen with weak intensity. This represented a unique case of T-LGL leukemia showing a typical clinical and phenotypic features.     

Gammadelta T-cell large granular lymphocyte (LGL) leukemia with spontaneous remission

T-cell large granular lymphocyte (LGL) leukemia is a clonal disorder with an indolent clinical course. In July 1995, a 46-year-old Japanese man was admitted to our hospital because his anemia had progressed. He had a white blood cell count of 3.9 x 10(9)/L with 75% lymphocytes, which were intermediate to large and had almost round nuclei and azurophilic granules, and anemia with a red blood cell count (RBC) of 2.69 x 10(12)/L, hemoglobin (Hb) of 9.5 g/dL, and hematocrit (Hct) of 28.3%. Electron microscopic examination showed that most of the lymphocytes had a parallel tubular array and dense core granules in their cytoplasm. Flow cytometry and Southern blotting of the T-cell antigen receptor (TCR) genes using the peripheral blood species showed monoclonal proliferation of LGLs with a CD3+, TCRgammadelta+, CD4-, CD8-, CD16+, CD56-, CD57-, HLA-DR+ phenotype, and a TCR gamma gene rearrangement, respectively, suggesting that the patient was diagnosed as having gammadelta T-cell LGL leukemia. He had no symptoms, organomegaly, or skin lesions. About 1.5 years after diagnosis, the anemia gradually improved with disappearance and appearance of a rearranged band in the TCR-gamma gene and TCR-beta gene, respectively. About 7 years after diagnosis, the anemia improved completely with a RBC of 5.01 x 10(12)/L, Hb of 14.8 g/dL, and Hct of 44.3%, and he was in complete remission without TCR-beta and -gamma gene rearrangements. He had received no therapy. This is the first report of spontaneous remission of gammadelta T-cell LGL leukemia.     

Primary gastric T-cell lymphoma not associated with human T-lymphotropic virus type I: a case report and review of the literature

Primary gastric T-cell lymphoma (PGTL) not associated with human T-lymphotropic virus type I (HTLV-I) is extremely rare and such a case is reported herein. The patient was a 58-year-old Japanese male presenting with submucosal tumor of the stomach identified on endoscopic examination. The lesion was diagnosed as non-Hodgkin's lymphoma by endoscopic biopsy and classified as peripheral T-cell lymphoma, unspecified, due to clonal rearrangement of the T-cell receptor beta (TCR) gene and expression of TCR beta protein in the absence of B-cell genotypes and phenotypes. Unlike previously reported cases of HTLV-I-unassociated PGTL, lymphoma in the current case was characterized histologically as "low grade" and phenotypically as CD4+, TIA-1+, granzyme B+, and CD103-. The lymphoma responded well to chemotherapy and radiation, and the patient was well with no detectable disease 10 months after initiation of therapy. A review of patients with PGTL in the literature revealed a few long-term survivors, and the investigation of therapeutic strategies for PGTL is, therefore, necessary.     

Gamma/delta T cell lymphoma

A 54-year-old woman complained of fever and hepato-splenomegaly. The pathological findings of a liver biopsy specimen revealed the infiltration of lymphocytes in the sinusoids and that of the laparoscopically resected spleen revealed the infiltration of lymphocytes in the red pulp, which was positive for CD3, CD43, CD45RO and T-cell intracellular antigen-1 (TIA-1) and was negative for betaF1, while the white pulp was spared. Genetic analysis of the spleen cells revealed the rearrangement of T-cell receptor (TCR) Cbeta1, Jdelta1 and Jgamma. Epstein-Barr virus (EBV) genomic DNA was detected in the spleen cells. Atypical lymphocytes appeared in the peripheral blood and bone marrow, chromosomal analysis revealed del (13) (q12 q14), trisomy 8 and breakage of RB gene. Elevated level of serum vascular endothelial growth factor (VEGF) was observed. Hepatosplenic gammadelta T cell lymphoma (GDTL) was diagnosed. The patient was treated with chemotherapy by cyclophosphamide, hydroxydoxorubicin, vincristine and prednisolone (CHOP), however, it was ineffective, and the patient died of hemorrhage from the lymphoma involvement of the intestine 5 months after the onset of disease.     

Lymphoproliferative disease of granular lymphocytes with T-cell receptor gamma delta-positive phenotype: restricted usage of T-cell receptor gamma and delta subunit genes

Lymphoproliferative disease of granular lymphocytes (LDGL) is characterized by more than 0.5 x 109/L of proliferating granular lymphocytes in the peripheral blood. Because of its rarity, the characteristics of LDGL with T-cell receptor (TCR) gammadelta phenotype (gammadeltaT-LDGL) have not yet been identified. This report describes the clinical, hematological, and immunological findings of four patients with this disease. In two cases, the clinical course was indolent and the other two patients required various therapies. The cells had a common immunophenotype: CD3+, CD4-, CD16+, CD56-, CD57-, CD122-, TCR-gammadelta+, and three were CD8-positive. The immunopurified TCR-gammadelta cells from the patients expressed only Vgamma9 and Vdelta1. Spectratyping and sequencing showed mono- or oligoclonality for TCRgamma and TCRdelta subunit genes. Soluble Fas ligand in sera was significantly elevated in all patients. These findings suggest that gammadeltaT-LDGL qualifies as a distinct disease entity.     

Small Cell Variant of T-Cell Prolymphocytic Leukemia with a γδ Immunophenotype

T-cell prolymphocytic leukemia (T-PLL) is a rare postthymic T-cell disorder. The disease is characterized by lymphadenopathy, splenomegaly, skin lesions, a high white blood cell count, and an aggressive clinical course. The small cell variant of T-PLL occurs in approximately 20% of patients. Most T-PLL patients express membrane T-cell receptors (TCR) of the alphabeta phenotype. The diagnosis of small cell variant T-PLL in a 56-year-old woman was based on the findings of abnormal lymphocytosis, immunophenotype, lymphadenopathy, and aggressive clinical behavior. Immunophenotype analysis showed that lymphocytes were positive for CD2, CD3, CD5, CD7, CD8, and TCR gammadelta antigens and negative for CD1a, CD4, and TCR alphabeta antigens. Southern blot analysis revealed rearrangement of the TCR Jgamma and Jdelta-1 genes. A cytogenetic study of peripheral blood showed a normal karyotype. T-PLL with a TCR gammadelta phenotype is very rare. This case was typical T-PLL except for the morphologically small cell type and the lack of the typical chromosome aberration. If cases accumulate in the future, the specific features of the gamma8 type of T-PLL will become clearer.     

Development of hepatosplenic gammadelta T-cell lymphoma with pancytopenia during early pregnancy: a case report and review of the literature

Lymphomas rarely develop during pregnancy, but hepatosplenic gammadelta T-cell lymphoma (HSgammadeltaTCL) is extremely rare. We encountered a case of T-cell intracellular antigen-1 (TIA-1) positive and granzyme B-positive HSgammadeltaTCL that developed early during the course of pregnancy. The patient was a 31-yr-old female who was referred to our hospital because of pancytopenia and splenomegaly at the time of the14th week of her gestation. Her pancytopenia and hepatosplenomegaly worsened and she became fibril at the 27th week of gestation and Cesarean section was performed at the 29th week. Histopathological examination of the spleen, which was resected 28 d after delivery for a diagnostic purpose, revealed medium to large-sized nodules composed of dense proliferation of lymphoid cells having round to oval-shaped nuclei and abundant weakly eosinophilic cytoplasm. They were CD3epsilon+, mCD3+, CD4-, CD8-, CD56+, CD79a-, T-cell receptor (TCR)-gammadelta protein+, TIA-1+, and granzyme B+ by either immunohistochemistry or flow cytometry. Clonal rearrangement of TCR-gamma genes without such rearrangement of TCR-delta and TCR-beta genes was confirmed by Southern blot hybridization. Thus, the patient was diagnosed as having HSgammadeltaTCL, and combination chemotherapy was initiated. She is currently in partial remission. To our knowledge, this is the first case report of HSgammadeltaTCL that developed during pregnancy. Pathogenesis of pregnancy-associated lymphoma is not known, but it is possible that maternal immunity during pregnancy or a hormonal imbalance, such as a change in the progesterone level, induces the development of lymphoma. Pregnancy-associated lymphoma is resistant to standard chemotherapy and is associated with poor prognosis. Therefore, it is important to accumulate clinicopathologic data of such cases for the development of a treatment modality.     

HIV感染者/AIDS患者外周血T细胞抗原受体γδT细胞的检测及其临床意义

目的　探讨外周血T细胞抗原受体 (TCR)γδT细胞在艾滋病病毒 (HIV)感染者 /艾滋病 (AIDS)患者疾病进程中的作用。方法　应用流式细胞仪采用三色荧光抗体染色技术分别检测 18例HIV感染者、2 9例AIDS患者、2 5例伴有机会性感染的AIDS患者、2 0例高效抗逆转录病毒联合疗法 (HAART)治疗后的AIDS患者及 2 0例正常对照者外周血的TCRγδT细胞与TCRαβT细胞。 结果　HIV感染者组和AIDS患者组的外周血TCRγδT细胞的百分率比正常对照组明显地增高 (P <0 0 1) ,而TCRαβT细胞的百分率明显地低于正常对照组 (P <0 0 1) ,AIDS患者组的CD+ 3 细胞的百分率明显地低于HIV感染者组和正常对照组 (P <0 0 1)。AIDS患者伴机会性感染组的外周血TCRγδT细胞的百分率明显地高于HAART治疗后的AIDS患者组 (P <0 0 1) ,该组的TCRαβT细胞的百分率及CD+ 3 T细胞的百分率则明显地低于经HAART治疗后的AIDS患者组 (P <0 0 1)。结论　TCRγδT细胞数量增多是机体受到病毒感染时的一种早期非特异性免疫反应 ,在AIDS的疾病进程中及机会性感染时起一定的免疫防御作用。     

Cytogenetics of childhood T-cell leukemia

The karyotypes of 57 cases of childhood T-cell acute lymphoblastic leukemia (ALL) were analyzed to establish the cytogenetic profile in this disease. Three questions were of particular interest. Do the chromosomal changes in T-cell ALL preferentially affect bands where genes encoding the T-cell receptor for antigen (TCR) have been mapped? Do alterations involving the TCR gene regions appear with any notable frequency in B-progenitor ALL? Do chromosomal abnormalities in this disease relate to stage of T-cell ontogeny? A relatively high proportion of cases (65%) had a pseudodiploid karyotype at presentation, the majority (58%) characterized by a translocation. The overall frequency of translocations was 44%, comparable to that among all banded cases of ALL seen in our laboratory. Hypodiploidy and hyperdiploidy were exceedingly rare (only four of 57 cases); 16 cases (28%) had apparently normal karyotypes. In half the cases with a translocation (14 of 24), the breakpoints were in regions to which the alpha and beta chain TCR genes have been mapped. Chromosomal breakpoints that were consistently observed in the vicinity of TCR gene loci were 7q32-q36 (TCR beta chain; n = 8), 14q11-q13 (TCR alpha chain; n = 6); other frequent breakpoints were 9p13-pter (n = 8) and 6q15-qter (n = 9). Chromosomal alterations occurred near TCR gene loci significantly more often in T-cell cases than in a comparison group of 335 patients with B-cell precursor ALL (26% v 1.5%, P = .0001). Stage I thymocyte development (CD7+, CD2+, CD5+, CD1-, CD3-, CD4-, CD8-) was noted in 23 cases, stage II (CD7+, CD2+, CD5+, CD1+, CD3-, CD4 +/-, CD8 +/-) in 25 cases, and stage III (CD9+, CD2+, CD1-, CD5+, CD3+, and either CD4+ or CD8+) in nine cases. The only statistically significant associations between cytogenetic findings and T-cell ontogeny were a higher frequency of normal karyotypes in cases with stage I thymocytes, and of pseudodiploidy in stage II cases. There was no apparent relationship between particular translocations and level of thymocyte maturation. Our findings indicate that most children with T-cell ALL have pseudodiploid karyotypes, although a surprisingly high percentage lack demonstrable abnormal clones. Specific chromosomal changes do not appear to be related to discrete stages of T-cell ontogeny as defined in this study, but they occur preferentially in bands containing TCR genes.     

Hepatosplenic gammadelta T-cell lymphoma is a rare clinicopathologic entity with poor outcome: report on a series of 21 patients

We report on the characteristics of 21 patients with hepatosplenic gammadelta T-cell lymphoma (HSgammadeltaTCL), an entity recognized since 1994 in the Revised European American Lymphoma (REAL) classification. Median age was 34 years. Patients had splenomegaly (n = 21), hepatomegaly (n = 15), and thrombocytopenia (n = 20). Histopathologic findings were homogeneous and showed the presence of medium-sized lymphoma cells within the sinusoids of splenic red pulp, liver, and bone marrow. Marrow involvement was usually mild but could be demonstrated by phenotyping in all patients. Cells were CD3+CD5-, expressed the gammadelta T-cell receptor, and had a nonactivated cytotoxic cell phenotype (TIA-1+, granzyme B-). Most patients were CD4-/CD8- (16 of 18); CD56+ (15 of 18), expressed the Vdelta1epitope (Vd1+/Vd2-/Vd3-) (9 of 12); and were negative for Epstein-Barr virus (EBV) (18 of 20). Isochromosome arm 7q was documented in 9 of 13 patients. Eight patients had previously undergone kidney transplantation or had a history of systemic lupus, Hodgkin disease, or malaria. Prognosis was poor; median survival time was 16 months, and all but 2 patients ultimately died despite consolidative or salvage high-dose therapy. In conclusion, HSgammadeltaTCL is a disease with distinctive clinical, histopathologic, and phenotypic characteristics. Bone marrow biopsy with combined phenotyping is sufficient for diagnosis, and splenectomy is therefore unwarranted. Current treatment modalities appear to be ineffective in most patients.     

T-gamma delta large granular lymphocyte leukemia preceded by pure red cell aplasia and complicated with hemophagocytic syndrome caused by Epstein-Barr virus infection

A 51-year-old man developed anemia, and was diagnosed with pure red cell aplasia through the absence of erythroid progenitors. Initially, he was treated with cyclosporine and prednisolone for 6 months but they were ineffective. Large granular lymphocyte (LGL) leukemia with the T-cell gamma delta phenotype evolved after 6 months showing CD2+, CD3+, CD8- and CD56- with the T-cell receptor beta gene rearrangement, clonalities of gamma and delta genes and complex chromosome abnormality simultaneously with hemophagocytic syndrome (HPS). Epstein-Barr virus (EBV) genomic DNA was detected in the bone marrow cells. Administration of bolus methylprednisolone was ineffective, and the patient died one month later. In the present patient, it seemed that lymphoproliferative disease of large granular lymphocytes (LDGL) manifested initially as PRCA, gammadelta LGL leukemia evolved, and finally fatal HPS become complicated, presumably caused by the EBV reactivation in the immunodeficiency state with the administration of immunosuppressants.     

Characterization of novel natural killer (NK)-cell and gammadelta T-cell lines established from primary lesions of nasal T/NK-cell lymphomas associated with the Epstein-Barr virus

Studies on nasal T/natural killer (NK)-cell lymphoma have been hampered by its tendency to cause necrosis. Thus, the establishment of cell lines of this neoplasm would seem to be valuable. This study attempted to establish cell lines from primary lesions of this tumor, and successfully obtained 2 novel Epstein-Barr virus (EBV)-positive cell lines, SNK-6 and SNT-8, by means of high-dose recombinant interleukin 2. Flow cytometry showed that SNK-6 had an NK-cell phenotype, CD3- CD4- CD8- CD19- CD56+ T-cell receptor (TCR) alpha/beta- TCR gamma/delta-, whereas SNT-8 was CD3+ CD4- CD8- CD19- CD56+ TCR alpha/beta- TCR gamma/delta+. These were consistent with immunophenotypes of their original tumors, and the cell lines had monoclonal EBV clones identical to ones in their original tumors. Thus, the cell lines developed from cells forming the primary lesions. Genotypic analysis showed that SNK-6 had unrearranged TCR and immunoglobulin heavy-chain genes, supporting the conclusion that SNK-6 was of NK-cell lineage. On the other hand, SNT-8 had rearranged TCR beta-, gamma-, and delta-chain genes, and together with its phenotype, SNT-8 proved to be a gammadelta T-cell line. This is the first report of the establishment of cell lines from primary lesions of nasal T/NK cell lymphomas, and the results demonstrated that there are at least 2 lineages, NK- and gammadelta T-cell, in this neoplasm. Moreover, it has been suggested that nasal T/NK cell lymphomas of these lineages may belong to the same clinicopathologic entity because both types of cases shared common clinical and histopathologic features.     

Late Epstein-Barr virus infection of a hepatosplenic gamma delta T-cell lymphoma arising in a kidney transplant recipient

BACKGROUND AND OBJECTIVE: gd T-cell lymphomas are only exceptionally observed in transplanted patients. Aim of this study was the detailed characterization of one such case. DESIGN AND METHODS: The patient developed spontaneous splenic rupture six years after kidney transplantation. The splenic red pulp was infiltrated by medium-sized and large lymphoid cells with two or more nucleoli. At autopsy, similar lymphoid cells infiltrated the hepatic sinusoids. Histologic, immunologic and molecular studies were carried out. RESULTS: By immunohistochemistry, the atypical lymphoid cells were found to express CD3, CD45 and CD43, indicating their T-lineage origin. Approximately 99% of spleen mononuclear cells (MNC) were CD3(+), gammadelta TcR+, CD4-, CD8-, alphabeta TcR-. A clonal gammadelta TcR rearrangement (Vgamma1-Jgamma1.3/2.3-Cgamma2; Vdelta1-Ddelta2-Jdelta1) was detected. The final diagnosis was peripheral T-cell lymphoma, hepato-splenic gammadelta-type. EBV infection of spleen MNC was documented by molecular studies. However, in situ hybridization for EBER-1 (EBV-RNA) showed that only a minority of malignant lymphoid cells (5-7%) were EBV-infected. INTERPRETATION AND CONCLUSIONS: It is concluded that EBV infection was as a late event involving an already transformed gd T-cell clone.     

Acquired immunodeficiency syndrome-associated T-cell lymphoma: evidence for human immunodeficiency virus type 1-associated T-cell transformation.

The majority of lymphomas in the setting of acquired, iatrogenic, or congenital immunodeficiencies are B-cell lymphoproliferations. We describe a rare T-cell lymphoma in a fulminantly ill patient infected with human immunodeficiency virus type 1 (HIV-1). The T-cell nature of the process was defined genotypically (monoclonal T-cell receptor beta-chain [CT beta] rearrangement) and phenotypically (CD45RO+, CD4+, CD5+, CD25+, CD8-, CD3- and negative for a variety of B-cell and monocyte markers). The CD4+, CD25+ (interleukin-2 receptor [IL-2R]) phenotype with production of IL-2 and IL-2R RNA is analogous to human T-lymphotropic virus type I (HTLV-I)-associated adult T-cell leukemia/lymphoma (ATLL); however, no HTLV-1 could be detected. Southern blot analysis did demonstrate monoclonally integrated HIV-1 within the tumor genome. Furthermore, the tumor cells were producing HIV p24 antigen as shown by immunohistochemistry. This is the first case of acquired immunodeficiency syndrome (AIDS)-associated non-Hodgkin's lymphoma in which HIV-1 infection may have played a central role in the lymphocyte transformation process.     

Transformation of T-cell large granular lymphocyte leukaemia into a high-grade large T-cell lymphoma

We describe a case of T-cell large granular lymphocyte (LGL) leukaemia that transformed into a large-cell T-cell lymphoma 11 years from diagnosis. A 29-year-old asymptomatic female presented in 1989 with lymphocytosis, neutropenia and mild bone marrow infiltration. The circulating cells were LGL with a CD2+, CD3+, CD8+, CD4-, CD16+, CD56+, CD57- phenotype. In August 2000, she developed fever, a large submandibular mass and hepatosplenomegaly. Biochemistry showed abnormal liver function tests and raised lactate dehydrogenase (LDH) levels. A serological screen for Epstein-Barr virus, cytomegalovirus, human T-lymphotropic virus-I, human herpes virus (HHV)-6 and HHV-7 was negative. Histology of the mass was consistent with the diagnosis of peripheral T-cell lymphoma composed of large cells, and immunohistochemistry showed that the lymphoma cells had a phenotype identical to the mature LGL. Molecular analysis with the polymerase chain reaction (PCR) demonstrated rearrangement of the T-cell receptor (TCR) gamma-chain gene with a band of identical size in both bone marrow mature LGL and lymph node cells. The patient was treated with CHOP (cyclophosphamide, vincristine, doxorubicin and prednisolone), resulting in the disappearance of the mass and improvement of the hepatosplenomegaly, LDH and liver abnormalities. She underwent splenectomy, and spleen histology showed involvement by T-cell LGL leukaemia with no evidence of transformation. This case illustrates that transformation or Richter syndrome may occur in a minority of patients with T-cell LGL leukaemia, a disease that has a benign clinical course in most cases. This is the first case documented by molecular methods of the transformation of the pre-existing clone.