European-American-type hairy cell leukemia without splenomegaly, treated successfully with deoxycoformycin]

A 55-year-old Japanese man was hospitalized on October 5, 1999, because of high fever. Physical examination revealed neither lymphadenopathy nor hepato-splenomegaly. Laboratory data on admission showed a white blood cell count of 1,580/microliter, a hemoglobin level of 9.1 g/dl, and a platelet count of 113 x 10(3)/microliter. A small percentage of abnormal mononuclear cells were present in the peripheral blood. A bone marrow biopsy specimen demonstrated myelofibrosis and diffuse infiltration of abnormal monoculear cells with a mature B cell phenotype. A bone marrow aspirate showed 29% abnormal mononuclear cells, which had an indented or folded nucleus and reticular nuclear chromatin. Moderate to strong tartarate-resistant acid phosphatase activity was detected in these cells. Although the cytoplasmic projections were poorly preserved in specimens stained with May-Giemsa, fresh preparations showed numerous slender cytoplasmic projections by phase-contrast microscopy. The hairy cells had the phenotype CD5-, CD10-, CD11c+, CD19+, CD20+, CD25+, lambda. The patient was diagnosed as having European-American-type hairy cell leukemia (HCL) without splenomegaly, which is quite rare in Japan. The value of phase-contrast microscopy for recognition of the hairy cells was emphasized. The patient was treated successfully with deoxycoformycin (DCF).     

Hairy cell leukemia and other "hairy-cell" lymphoproliferative disorders (LPD-HC): the significance of morphologic, histologic and immunologic studies

In this report the clinical, morphologic, histologic and immunologic findings of 41 patients with hairy lymphoid cells in peripheral blood and/or bone marrow are analyzed. In 27 patients the diagnosis of hairy cell leukemia was established. 14 patients had other variants of lymphoproliferative disorders: malignant lymphoma with hairy cells--7, chronic lymphocytic leukemia with hairy cells--5, and T cell lymphoproliferative disorder with hairy cells--2 patients, respectively. Several variants of malignant lymphoma with hairy cells were defined: lymphocytic, centrocytic and lymphoplasmacytic. The importance of combined use of bone marrow biopsy and immunophenotyping for the correct diagnosis of hairy cell leukemia and other "hairy-cell" lymphoproliferative disorders is stressed. The obtained data suggest relationship between characteristic clinical manifestation (isolated splenomegaly), presence of hairy cells and CD11c-antigen expression.     

Successful treatment with cladribine for hypoplastic hairy cell leukemia after long-term neutropenia

A 34-year-old woman was admitted to the hospital because of swelling of her right knee, and the result of the laboratory tests indicated anemia and leukocytopenia. A bone marrow examination showed dissemination of small to medium-sized abnormal lymphocytes with abundant and pale blue cytoplasm and a circumferential "hairy" projection in the hypocellular bone marrow. These cells were positive for tartrate-resistant acid phosphatase (TRAP) and for CD 19, CD 20, CD 25, CD 103 and SmIg kappa. The patient was diagnosed as having hypoplastic hairy cell leukemia and received cladribine (2-CdA) for seven days via continuous intravenous injection. The minimum white blood cell count was 300/microl at seven days after starting the therapy (day 7) and the neutrophil count recovered to more than 1500/microl on day 118. The patient achieved complete remission on day 140 without any episodes of severe infection and has remained in complete remission for more than one year. The treatment of hypocellular HCL with 2-CdA might be useful.     

1 alpha(OH) D3 (Alfarol) is effective for the treatment of chronic B cell leukemia: a case report

We reported a case of chronic B-cell leukemia reacted to the administration of 1 alpha (OH)D3 (Alfarol-CHUGAI Pharm. Co.), The patient showed pancytopenia with IgM-kappa type monoclonal protein in the serum. The bone marrow aspiration was failed due to a dry tap, but the biopsied specimen showed a marked infiltration of small sized lymphoid cells with wide cytoplasm. The leukemic cells from peripheral blood showed a morphology of atypical hairy cells, Surface markers of the leukemic cells were IgM, D(kappa)+, CD 19+, CD 20+, CD 21- and HLADR+, The leukemic cells showed no L-tartrate resistant acid phosphatase sensitivity. This case was diagnosed as a chronic B-cell leukemia closely related to a hairy cell leukemia. The treatment with estrogen-chlorambucil compound (Bestrabucil-KUREHA Chem, Co.) or splenic irradiation was not effective. However, after two months' administration of Alfarol the regular blood transfusion was not needed because of increment of the Hb concentration. After eight months of its administration, the bone marrow aspirate showed a marked decrease in the number of the leukemic cells and a restoration of normal hematopoietic cells. This experience suggested that Alfarol in usefull for the treatment of chronic B cell leukemia including hairy cell leukemia and chronic lymphocytic leukemia.     

Hairy cell leukemia successfully treated with deoxycoformycin]

A 45-year-old male was hospitalized on September 2, 1989 with chief complaints of general fatigue and fever. Physical examination revealed hepatomegaly and massive splenomegaly. Laboratory tests on admission showed Hb of 7.5g/dl, PLT 4.8 x 10(4)/microliters and WBC 9,610/microliters with 81% hairy cells. Bone marrow aspirate demonstrated 55.1% hairy cells and moderate myelofibrosis. Cytochemically, hairy cells were positive for tartrate-resistant acid phosphatase (TRAP). Surface markers were SmIg G+ A+ kappa +, CD11b+, CD11c+, CD19+, CD20+, CD21-, CD25+, HC2+, HLA-DR+. From these findings, a diagnosis of hairy cell leukemia (HCL) was made. After administration of deoxycoformycin (DCF) at a dose of 5.0mg/m2 1-2 times monthly, splenomegaly disappeared, as did hairy cells from the peripheral blood. Hematological level returned to within normal range except for the presence of 1.2% hairy cells and mild myelofibrosis in bone marrow aspirates. DCF has so far been effective for this patient. While DCF has been reported to be effective in the treatment of HCL in the West, it has not been determined in Japanese patients with HCL, who have different hematologic features from those of HCL patients in the West.     

Detection of hairy cell leukaemia in blood and bone marrow using multidimensional flow cytometry with CD45‐PECy5 and SS gating

CD45 and right angle light scatter (SS) gating are used commonly in clinical flow cytometry to differentiate cells of various lineages ( 10 ). We have used CD45‐PECy5 (Clone J33) since 1998 and have noticed that malignant lymphoid cells such as hairy cells can form distinct populations. Previous studies indicate that hairy cells reside where normal monocytes are usually found in CD45/SS scatter plots ( 14 ). We studied six patients with hairy cell leukaemia (HCL) and found that hairy cells have a higher CD45 mean cell fluorescence than normal lymphocytes and monocytes. Two of the six patients presented with mild unexplained cytopenias, without the usual clinical, morphological and cytochemical findings. In both cases, CD45/SS gating of bone marrow cells showed a small population with strong expression of CD45. The presence of hairy cells was confirmed using a panel of monoclonal antibodies. In one patient with HCL variant, CD45 expression was indistinguishable from that of normal lymphocytes. We conclude that CD45‐PECy5 (Clone J33) is useful for screening peripheral blood and bone marrow and for the detection of HCL without obvious morphological involvement.     

A hairy B cell lymphoproliferative disorder resembling hairy cell leukemia

This case report describes a hairy B cell lymphoproliferative disorder (HBLD) with clinical and hematological features resembling hairy cell leukemia. The patient was a 29-year-old female who demonstrated atypical lymphocytes in her peripheral blood. Physical examination demonstrated splenomegaly, but there were no palpable superficial lymph nodes. Hematological examination showed a leukocyte count of 10.6 x 10(3)/mm3 with 41% atypical lymphocytes. Bone marrow examination showed a normal cellular and an atypical lymphocyte count of 42%. The atypical lymphocytes had microvilli and prominent membranous ruffles on their surfaces. Atypical lymphocytes expressed CD5- CD10- CD11c+ CD19+ CD20+ CD23- CD25- on the surface of the cells on examination by with a fluorescence activated cell sorter. Although these findings were similar to hairy cell leukemia, Japanese variant, the surface marker of the kappa chain and lambda chain was unbiased and studies of immunoglobulin gene rearrangements and expression showed polyclonal proliferation of B cells. Therefore, we diagnosed this patient as having HBLD. Because she did not demonstrate anemia or thrombocytopenia, she is not currently receiving medication. To date, the atypical lymphocyte count has not changed.     

Detection of hairy cell leukaemia in blood and bone marrow using multidimensional flow cytometry with CD45-PECy5 and SS gating

CD45 and right angle light scatter (SS) gating are used commonly in clinical flow cytometry to differentiate cells of various lineages (Stelzer et al., 1993). We have used CD45-PECy5 (Clone J33) since 1998 and have noticed that malignant lymphoid cells such as hairy cells can form distinct populations. Previous studies indicate that hairy cells reside where normal monocytes are usually found in CD45/SS scatter plots (Wells et al., 1998). We studied six patients with hairy cell leukaemia (HCL) and found that hairy cells have a higher CD45 mean cell fluorescence than normal lymphocytes and monocytes. Two of the six patients presented with mild unexplained cytopenias, without the usual clinical, morphological and cytochemical findings. In both cases, CD45/SS gating of bone marrow cells showed a small population with strong expression of CD45. The presence of hairy cells was confirmed using a panel of monoclonal antibodies. In one patient with HCL variant, CD45 expression was indistinguishable from that of normal lymphocytes. We conclude that CD45-PECy5 (Clone J33) is useful for screening peripheral blood and bone marrow and for the detection of HCL without obvious morphological involvement.     

CD5+ immunophenotype in the bone marrow but not in the peripheral blood in a patient with hairy cell leukemia

We report the case of a patient with rare CD5+ hairy cell leukemia, which was unusual, as there was also a discrepancy between the bone marrow and peripheral blood immunophenotypes. We propose that some degree of maturation within the malignant clone and the predominance of more mature CD5- hairy cells in the peripheral blood can explain this observation. The patient was treated with a conventional course of cladribine (2'-chlorodeoxyadenosine) and achieved complete remission. We conclude that the unusual CD5+ immunophenotype of this patient did not affect prognosis or change the response to standard therapy.     

Preferential infiltration of liver sinusoids in acute lymphoblastic leukemia

We report a case of acute lymphoblastic leukemia (ALL) presenting as severe jaundice. The patient, a 59-year-old man, was found to have abnormal liver function, including an elevated total bilirubin level (13.5 mg/dl) with hepatosplenomegaly, but no detectable lymphadenopathy. A liver biopsy and bone marrow examination revealed a lymphoid neoplasm. Pathologic features included invasion of an abnormal clone into the sinusoidal region of the liver, diffuse bone marrow involvement (41.6% of all nucleated cells) and splenomegaly. Small numbers of malignant cells were also detected in the peripheral blood. B-cell markers, such as terminal deoxynucleotidyl transferase (TdT), CD10, CD19, CD20 and HLA-DR were positive, and CD2, CD3, CD4, CD5, CD7, CD8, kappa, lambda, cytoplasmic mu and myeloperoxidase were negative. Cytogenetic analysis detected hyperdiploidy. In this case, a dose-attenuated CHOP regimen attained complete remission. To date, preferential infiltration to liver sinusoids has been noted in hepatosplenic gamma/delta T-cell lymphoma, other NK/T-cell malignancies, and some cases of hairy cell leukemia. Severe jaundice due to preferential infiltration of leukemic cells into liver sinusoids is rather uncommon as a presenting feature of ALL.     

CD56+CD7+ stem cell leukemia/lymphoma with D2-Jdelta1 rearrangement.

OBJECT: We describe the characteristics of three patients with CD56+CD7+ stem cell leukemia/lymphoma. METHODS: These blasts were analyzed for morphologic, karyotypic, immunophenotypic, and immunogenotypic features using Southern blot and polymerase chain reaction analysis. MATERIALS: Peripheral blood, bone marrow aspirates, or biopsied mediastinal tumor specimens of three CD56+CD7+ stem cell leukemia/lymphoma patients were investigated. RESULTS: The bone marrow of all patients showed myeloperoxidase (MPO) negative blast cells with basophilic cytoplasm and distinct nucleoli with no azurophilic granules. The blasts of two patients were classified as acute lymphoblastic leukemia (L2). The liver, spleen, and lymph nodes were unaffected in all patients. All had an aggressive clinical course. The blasts were strongly positive for both CD7 and CD56 but negative for other T-lineage associated antigens, including CD1, CD2, surface membrane CD3, cytoplasmic CD3c (2/2), CD4, CD5 and CD8. The additional antigens were recognized as follows: CD19 (1/3 cases) as a B lineage, CD33 (1/3) as a myeloid marker, CD34 (2/3) as a stem cell, CD38 (1/1) and HLA-DR (2/3). When the patients relapsed, the phenotypes changed to blasts positive for CD5, CD10 and CD13 in patient 1, CD5 in patient 2, and CD33 in patient 3. MPO, however, remained negative. Cytogenetic analysis showed no common abnormal karyotype. All had a common D2-Jdelta1 induced by T-cell specific enhancer. Rearrangement of TCR beta and gamma genes occurred in patient 2, and IgH and TCR beta underwent rearrangement in patient 3. CONCLUSION: Although a more comprehensive case analysis is necessary, these data suggest the possibility that the blasts of the present cases come from a common lymphoid precursor (T, NK, and B cell) or from a NKT precursor as the fourth lymphoid lineage.     

Hairy cell leukemia, Japanese variant, successfully treated with cladribine

A 67-year-old male was admitted because of lymphocytosis and huge splenomegaly. Abnormal lymphocytes had cytoplasmic hairy projections and were negative for tartrate-resistant acid phosphatase staining. The bone marrow aspirate contained many lymphocytes with the same morphology. Flow cytometric analysis revealed an increase in IgM and kappa positive B cells. They were positive for CD11c, CD19, CD20 and FMC7, and negative for CD5, CD10 and CD25. The patient was diagnosed as having hairy cell leukemia, Japanese variant. Initially interferon-alpha was administered for a month, decreasing the numbers of leukemic cells but with little effect on splenomegaly. Subsequent administration of cladribine (0.09 mg/kg, 7 days) showed a remarkable effect, and the patient has been in complete remission for 8 months.     

Intensive chemotherapy of hairy cell leukemia in patients with aggressive disease

Seven patients with hairy cell leukemia were treated by intensive chemotherapy because they were considered to have a progressive disease and a poor short-term prognosis. The mean age was 47 years (range, 36 to 58). Six of seven patients had prior splenectomies with minor or transient hematologic responses. One patient had no spleen enlargement. The seven patients had never received any cytotoxic drugs and had prolonged granulocytopenia (less than 300/microL) with recurrent, severe infectious episodes. Chemotherapy included Rubidazone (zorubicine hydrochloride) 450 mg/m2 on day 1, arabinosyl cytosine 200 mg/m2/d from day 1 to day 5, and cyclophosphamide, 2,000 mg/m2 on day 5. Responses were assessed through examination of repeat bone marrow biopsy specimens and blood counts. A complete response was defined as normal blood counts associated with the disappearance of hairy cell infiltration and fibrosis on the bone marrow biopsy specimens. A partial response was defined as normal blood counts with persistence of leukemic cells in the bone marrow. Three patients achieved a complete response, and one patient had a partial response. Three patients died of infectious complications during induction chemotherapy. For the responding patients, the mean duration of aplasia was 37 +/- 5 days. Follow-up for the responding patients has been 44+, 24, 32+, and 23+ months. One patient with a complete response died while on maintenance therapy. We conclude that complete and prolonged histologic remission of hairy cell leukemia can be obtained with intensive chemotherapy. The toxicity of chemotherapy is such, however, that progressive disease after splenectomy needs to be more clearly defined.     

Hairy cell leukemia expressing SIgM+, SIgG-, CD11b+ and CD21+ and accompanying lymphadenopathy without splenomegaly]

Hairy cell leukemia (HCL) expressing both surface monocytoid antigen and IgM (kappa) was reported. A 62-year-old male was admitted to our hospital in September 21, 1989 because of leukocytosis. Physical examinations showed axillary and inguinal lymphadenopathy but no hepato-splenomegaly. The leukocyte count was 12,600/microliters with 73% of abnormal cells like large lymphocytes which had abundant cytoplasm and hairy appearance under phase microscopy. They had ruffles with microvilli under electron microscope. Bone marrow puncture showed normocellular marrow with 71.2% of abnormal cells similar to the peripheral blood. Surface markers were CD11b+, CD21+, HLA-DR+, Tac- and IgM (kappa). They were positive for ++acid phosphatase staining, but negative for peroxidase and tartrate-resistant acid phosphatase staining. He was diagnosed as Japanese type HCL. HCL expressing both surface monocytoid antigen and IgM is rare and the clinical features of our case are compared with those reported in Japan.     

CD25 positive chronic eosinophilic leukemia with myelofibrosis

A 70-year-old man was referred to our hospital in March 2001 for the purpose of evaluation for anemia and thrombocytopenia. Physical examination revealed hepatosplenomegaly, normal skin, and normal neurologic findings. Blood examination showed a white blood cell count of 10,900/microliter, with a differential count of 58.5% eosinophils and 3.5% blast cells. Flow cytometric analysis of eosinophils revealed that they were positive for CD33, CD13, CD25, and HLA-DR. Bone marrow aspiration could not be performed due to dry tap, and bone marrow core biopsy specimen revealed severe myelofibrosis with blastoid cells proliferation. Cytogenetic analysis of bone marrow cells showed isochromosome 17. FISH analysis using a RAR alpha probe (17q21.1) demonstrated 62% of peripheral blood nucleated cells having three signals. BCR/ABL gene rearrangement by FISH analysis was not observed. Allergic disease, infectious disease, parasitic disease, collagen vascular diseases, pulmonary disease, and neoplastic disorders were excluded. Therefore, a diagnosis of chronic eosinophilic leukemia was made. The patient had no symptoms of hypereosinophilia. However, eosinophils with sparse granulation, positivity for CD25, elevated serum levels of soluble IL-2 receptor, and elevated serum levels of eosinophil cationic protein suggested activation of eosinophils. Further analysis is needed regarding the activation of eosinophils in chronic eosinophilic leukemia.     

CD43 in B-cell chronic lymphocytic leukemia

CD43 (other names: sialophorin, leukosialin, sialoglycoprotein of white blood cells) is an integral cell membrane mucin. In population of peripheral B cells CD43 occurs only on activated B cells and CD5 positive B cells. These last cells create neoplasm population in patients with B-cell chronic lymphocytic leukemia (B-CLL). Anti-CD43 monoclonal antibodies are used routinely in investigations of tissue fragments in cases of non-Hodgkin's lymphoma, whereas we did not find publication on theme of CD43 expression on peripheral blood B cells in patients with B-cell chronic lymphocytic leukemia. Wherefore advisable appeared estimation CD43 expression on B-CLL cells and comparison it with expression of typical B-CLL markers--such as CD5 and CD6. Immunological phenotype of peripheral blood and bone marrow lymphocytes has been evaluated using flow cytometry (Cytoron Absolute Ortho-Diagnostic Systems) and two-color staining. Twenty six untreated patients with B-CLL were studied. Because on well-known correlations between CD43 expression and metastasis potential of tumor, patients were divided on two groups differing score of total tumor mass (score TTM). Score TTM was evaluated according to criterion of Jaksic and Vitale. Twelve patients whose TTM score was equal or lower than 9 and median lymphocytosis was 24.6 x 10(9) in microliter were included in group I. 14 patients whose TTM score was higher than 9 were included in group II. Median lymphocytosis in these patients was 152.6 x 10(9) in microliter. The median percentage of CD43+/CD19+ cells in peripheral blood was 62.6% in the group I, and 75% in the group II (p < 0.05). Median fluorescence intensity (MFI) of CD43 antigen was 87.7 in the I group comparing to 77.4 in the group II. So one observed tendency to lowering MFI during tumor growing but the difference was not significant (p = 0.25). In peripheral blood during progression of disease more clearly than CD43+ cells increased percentage of CD5+ and CD6+ cells. The median percentage of CD19+/CD5+ cells was 62.7% in the group I, 82.4% in the group II and the difference was significant (p < 0.002). The difference in the median percentages CD6+/CD19+ cell 71.8% in group I and 84.3% in the II one were also significant (p < 0.03). MFI of CD5 and also CD6 antigens did not change in course of disease. Moreover, examination of CD43 and CD5 expression in marrow additionally to blood study were performed in 12 cases (6 from group I, 2 from group II and 4 new not included). The median percentage of CD43+/CD19+ cell was 35.1% in blood and 43.7% In marrow, in contrast to these results was the median percentage of CD19+/CD5+ cell, which was higher in peripheral blood (70.4%) than in bone marrow (60.9%). The results of this study indicate that CD43 is present on peripheral blood B-CLL cells. Moreover, percentage of these cell increases during progression of disease however more weakly than percentage of CD5 and CD6 positive cells. Expression of CD43 is independent from expression CD5 and CD6 and diminishes during tumor mass increasing, what can depended from releases exocellular domains of CD43. CD43+ cell from B-CLL patients have a tendency to accumulation in tissues what is illustrated by higher percentage of CD43+ cell in bone marrow than in peripheral blood.     

Plasma cell leukemia presenting with circulating villous lymphocytes and an indolent clinical course

A 73-year-old man was admitted to our hospital in July 1996 because of lymphoctyosis and lumbago. Physical examination revealed hepatomegaly and anemia. Hematologic examination showed a hemoglobin concentration of 9.6 g/dl and a leukocyte count of 32,700/microliter with 74% abnormal mononuclear cells. In Wright-Giemsa stained blood films, these cells had short villi arising from 1 or 2 poles. Immunophenotyping of peripheral mononuclear cells showed moderate to strong expression of CD10, CD24, CD38, and sIg lambda, but not of CD19, CD20, or CD25. Southern blot analysis of the peripheral mononuclear cells demonstrated rearranged monoclonal bands in the C lambda. Urine immunoelectrophoresis detected a monoclonal band identifiable as lambda-type Bence Jones protein. In addition, bone X-ray studies disclosed multiple osteolytic lesions. A diagnosis of plasma cell leukemia was made, and the patient was placed on chemotherapy consisting of cyclophosphamide and prednisolone. No notable improvement in laboratory findings was seen but the patient experienced an indolent clinical course. He died of pneumonia in January 1998. The morphological and clinical findings were unusual for a case of plasma cell leukemia. This case study suggested that signs of lymphocytosis require immunophenotypic and electron microscopic studies for the differential diagnosis of plasma cell leukemia.     

Autologous transplantation of Ph-negative peripheral blood stem cells for treatment of chronic myelogenous leukemia

A 21-year-old man, diagnosed in March 1997 as having chronic myelogenous leukemia (CML), received hydroxyurea followed by daily interferon (IFN) until December 1998, when the additional chromosome abnormality of +8 appeared. As no suitable matched donor was available, the patient received mobilization therapy consisting of mini-ICE (idarubicin, cytarabine, etoposide) followed by G-CSF subcutaneously. During hematopoietic recovery, a total of 12 x 10(6)/kg CD34-positive cells were harvested. Cytogenetic analysis of peripheral blood stem cell (PBSC) products using FISH revealed 1% BCR/ABL fusion signals. In March 1999, he received conditioning therapy consisting of busulfan (16 mg/kg) and cyclophosphamide (120 mg/kg) followed by infusion of 5 x 10(6)/kg CD34-positive cells. A neutrophil count of 500/microliter and a platelet count of 5 x 10(4)/microliter were attained by days 20 and 38, respectively. Bone marrow aspirates showed 2.6% BCR/ABL fusion signals on day 35 after autologous PBSC transplantation, and the patient remained in chronic phase until the sixth month, when a cytogenetic relapse (Ph, +8:4/20) occurred. These observations suggest that Ph-negative progenitor cells can be harvested using a mini-ICE regimen followed by G-CSF, and that autologous PBSC transplantation is feasible in patients with CML resistant to IFN.     

The diagnosis of hairy cell leukemia can be established by flow cytometric analysis of peripheral blood, even in patients with low levels of circulating malignant cells.

The diagnosis of hairy cell leukemia (HCL) has traditionally been based on microscopic means. Immunophenotypic analysis of peripheral blood by flow cytometry is not widely recognized as a method for diagnosing HCL, perhaps due to the expectation of low yield of neoplastic cells in patients who are characteristically leukopenic. The abnormal coexpression of CD103, CD25, and intense CD11c and CD20 on monotypic, slightly large B-lymphocytes has previously been shown to be highly characteristic of HCL. We wished to determine if this pattern was valuable in the diagnosis of HCL in leukopenic patients with low levels of neoplastic cells in the peripheral blood. The abnormal immunophenotype above was observed in 25 peripheral blood specimens from patients with unexplained cytopenias or suspected lymphoproliferative processes. Ten of the 25 blood samples exhibited this abnormal phenotype in less than 5% of circulating leukocytes (ranging from <1% to 4%). All 10 patients had other manifestations of HCL, including cytopenias (mean white blood cell count, 1.8 x 10(3)/mm(3); hemoglobin, 11.0 gm/dl; platelets, 74 x 10(3)/mm(3)), splenomegaly, and typical bone marrow morphologic changes. Eight of the 10 patients achieved an excellent response to one course of 2-CDA, with significant improvement of cytopenias (mean white blood cell count: 5.3 x 10(3)/mm(3); hemoglobin: 14.4 g/dl; platelets: 181 x 10(3)/mm(3)) and regression of splenomegaly. One patient had a partial response to alpha interferon and a subsequent complete response to 2-CDA, and one died during treatment. In conclusion, flow cytometric immunophenotyping of peripheral blood is capable of detecting low levels of circulating malignant cells in HCL, even in leukopenic patients. As such, it can be a very useful, non-invasive tool in the diagnosis of this disorder.     

CD7(+) acute myeloid leukemia (M0) associated with a mediastinal bulky mass lesion

A 41-year-old man visited his doctor in May 2000 because of a sore throat and high fever. His symptoms did not improve, despite administration of antibiotics and nonsteroidal anti-inflammatory drugs. Since a chest X-ray examination revealed an anterior mediastinal bulky tumor, he was referred and admitted to our hospital on June 21, 2000. The peripheral white blood cell count was 44,540/microliter with 74% myeloblasts. Bone marrow aspiration revealed a hypercellular marrow with 82% myeloblasts, which were negative for peroxidase and alpha-naphthyl butylate esterase staining. Blast cells were positive for CD7, CD13, CD33, CD34, and HLA-DR, and negative for CD56. A needle biopsy specimen of the mediastinal tumor consisted of myeloblasts. We diagnosed the patient as having CD7 (+) acute myeloid leukemia (AML) (M0) with a bulky mediastinal mass based on the surface marker analysis, although the clinical features resembled myeloid/NK precursor acute leukemia. The patient achieved a complete remission after two courses of induction therapy. We are planning an allogeneic stem cell transplantation during his first remission because of the high risk of relapse.