Polycythemia vera (PV) is characterized by low serum total cholesterol despite its association with vascular events such as myocardial and cerebral infarction. Serum cholesterol level has not been used as a diagnostic criterion for PV since the 2008 revision of the WHO classification. Therefore, we revisited the relationship between serum lipid profile, including total cholesterol level, and erythrocytosis. The medical records of 34 erythrocytosis patients (hemoglobin : men, > 18.5 g/dL ; women, > 16.5 g/dL) collected between August 2005 and December 2011 were reviewed for age, gender, and lipid profiles. The diagnoses of PV and non-PV erythrocytosis were confirmed and the in vitro efflux of cholesterol into plasma in whole blood examined. The serum levels of total cholesterol, low-density-lipoprotein cholesterol (LDL-Ch), and apolipoproteins A1 and B were lower in PV than in non-PV patients. The in vitro release of cholesterol into the plasma was greater in PV patients than in non-PV and non-polycythemic subjects. Serum total cholesterol, LDL-Ch, and apolipoproteins A1 and B levels are lower in patients with PV than in those with non-PV erythrocytosis. The hypocholesterolemia associated with PV may be attributable to the sequestration of circulating cholesterol into the increased number of erythrocytes. [J Clin Exp Hematopathol 52(2) : 85-89, 2012]

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Diffuse large B-cell lymphoma (DLBCL) is the most common form of non-Hodgkin's lymphoma. Although many investigations have been performed on the prognostic factors of DLBCL, no reports have focused on localized nodal DLBCL. We examined the prognostic significance of 39 Japanese patients with localized nodal DLBCL with special reference to the germinal center B-cell-like (GCB) versus non-germinal center B-cell-like (NGCB) types. The median age was 65 years with 23 males and 16 females. Using Hans algorithm of immunohistochemistry, 18 patients (46%) exhibited GCB type and 21 (54%) exhibited NGCB type. Twenty-nine patients (74%) presented with disease in the neck (neck group) and 10 (26%) had disease in non-neck regions (non-neck group). Comparing Hans, Choi, and Muris algorithms, patients with GCB type showed statistically significant progression-free survival (PFS) only with Hans algorithm (P = 0.022, P = 0.100, and P = 0.130, respectively). Patient survival analyses revealed that GCB-type patients by Hans algorithm had a better PFS (P = 0.012), and neck-group patients had better PFS and overall survival (OS) (P = 0.018 and P = 0.012, respectively). Univariate analysis revealed that only neck vs. non-neck exhibited a significant difference in terms of OS (P = 0.026). Multivariate analysis revealed that GCB type by Hans algorithm and neck vs. non-neck were significantly different in terms of PFS (P = 0.025 and P = 0.033, respectively). Therefore, the subclassifications of GCB type vs. NGCB type and neck vs. non-neck are important predictive prognostic factors in localized nodal DLBCL. [J Clin Exp Hematopathol 52(2) : 91-99, 2012]

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Aggressive natural killer cell leukemia (ANKL) is a rare malignant disease of NK cells that has a median survival of less than 2 months and a strong association with the Epstein-Barr virus. Herein, we report three Japanese cases of the disease. A 21-year male patient, a 31-year female patient, and a 76-year female patient presented with high fever, lymphadenopathy, hepatosplenomegaly, and severe liver damage. All three cases had granular lymphocytes in both peripheral blood and bone marrow. The phenotype of these cells was CD2⁺CD3^-CD56⁺HLA-DR⁺. All cases had a high copy number of serum Epstein-Barr virus DNA in the peripheral blood and were diagnosed with ANKL. Case 1 and Case 2 were treated with chemotherapy, but suffered from gross intestinal bleeding or massive bleeding in the cerebellum, resulting in death. Although not treated with chemotherapy, Case 3 also suffered gross bleeding from an atypical duodenal ulcer and died from hemorrhagic shock 15 days after admission. There have been no previous reports of such acute lethal hemorrhagic complications with ANKL. The present cases suggest that patients with ANKL need a sufficient supply of coagulation factors, and that chemotherapy for this disease should be carefully designed with promising agents. [J Clin Exp Hematopathol 52(2) : 101-106, 2012]

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Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy with a poor prognosis. We encountered a unique case of BPDCN that was leukemic at presentation without skin lesion and expressed CD33 antigen. A 74-year-old man was admitted because of dyspnea. Physically, hepatosplenomegaly, but not skin lesions and superficial lymph node swelling, was noted. The white blood count was 33.6 × 10⁹/L with 19% giant abnormal cells. These cells were positive for CD4, CD86, CD123 (bright), BDCA-2, and HLA-DR, but negative for CD1a, CD3, CD11b, CD11c, CD13, CD14, CD19, CD64, and CD68. From these findings, a diagnosis of BPDCN was made. In terms of unusual expression, these tumor cells were positive for CD33 but negative for CD56. The karyotype was 47, XY, t(6;8) (p21;q24), + r. We performed combination chemotherapy (Ara-C + VP-16 + MIT), which resulted in a marked reduction of tumor cells and improvement of the dyspnea. On day 16, however, he died of sepsis due to Bacillus cereus. The clinical picture of this patient is unusual and may provide new information on the clinicopathology of BPDCN. [J Clin Exp Hematopathol 52(2) : 107-111, 2012]

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We describe a 65-year-old woman with follicular lymphoma (FL), grade 1, stage IV, which occurred concurrently with B lymphoblastic leukemia/lymphoma. Through the evaluation of FL, the cells that were morphologically suspected of having undergone transformation were found in the bone marrow, and flow cytometric and cytogenetic analyses detected the transformed population that suggested concomitant t(8;22) with typical t(14;18) FL cells. Repeated analyses of the lymph nodes demonstrated the typical morphological, phenotypic, and cytogenetic features of FL. The patient received several multiagent chemotherapy regimens, but the disease gradually became resistant, and the patient died of leukemic progression. In B-cell malignancies, cases involving both BCL2 and MYC translocations simultaneously, so-called “double-hit leukemia/lymphoma (DHL)”, have occasionally been reported. Patients with this type of translocation have a very poor clinical outcome, and no standard therapy has been established. In our case, FL was supposed to have transformed into B lymphoblastic leukemia via Burkitt's lymphoma-like phase. Our case is unique in that the transformed DHL cells, derived from clonally related FL cells, showed ongoing transformation from Burkitt-like feature to B lymphoblastic leukemia exclusively in the bone marrow, which suggests that the bone marrow may provide a preferable milieu for malignant transformation. Similar cases should be accumulated and analyzed carefully. [J Clin Exp Hematopathol 52(2) : 113-119, 2012]

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Langerhans cell histiocytosis (LCH) is a clonal neoplasm that shows diverse clinical manifestations and courses of disease progression. The etiology and pathophysiology of LCH remain uncertain. We describe the clinical course of a 23-year-old Japanese woman with multi-system LCH, who showed rapid progression after steroid reduction and developed multi-organ failure. Liver biopsy showed LCH infiltration with fatty degeneration. She was treated with cytarabine, vincristine, and prednisolone according to the Japan LCH study group 02 protocol, without any clinical improvement. Low expression of Ki67 and bcl-2 failed to explain the rapid clinical course. Panhypopituitarism and hypothalamic dysfunction may have caused nonalcoholic fatty liver disease and liver failure. This case indicates that some multi-system LCH patients with hypopituitarism and hypothalamic dysfunction show very rapid progression and are difficult to treat. [J Clin Exp Hematopathol 52(2) : 121-126, 2012]

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Forty-eight patients with gastrointestinal (GI) tract B-cell lymphoma (BCL) were analyzed retrospectively. The diagnosis was based on the histological examination of specimens obtained by endoscopic biopsy. Before the diagnosis was made, single-color flow cytometry was performed to analyze the expression of light chains and B-cell antigens including CD10 in the specimens. Restricted light chain (RLC) expression, a marker of B-cell clonality, was defined as κ and λ ratios of either more than 3.0 or less than 0.5. The specimens from 30 patients (62.5%) showed RLC expression. No RLC expression or RLC expression not examined was divided into two groups : those showing CD10 positivity in more than 20% of cells (4 patients, 8.3%) and those showing no positivity (14 patients, 29.2%). The cell number analyzed in the latter group was significantly smaller than that in the other two groups. Abnormal karyotypes were found in the specimens from 8 patients (16.7%). These results indicate that the flow cytometric analysis of endoscopic biopsy specimens is useful when BCL is suspected if an adequate number of cells are obtained. [J Clin Exp Hematopathol 52(2) : 127-131, 2012]

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A 71-year-old woman presented with massive splenomegaly. Open splenectomy was performed, and the diagnosis of peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), was made, with a characteristic immunophenotype of CD3⁺, CD4^-, CD8^-, T-cell receptor (TCR)αβ⁺, and TCRγδ^-. After splenectomy, she suffered abrupt exacerbation of the lymphoma with disseminated intravascular coagulation and enteropathy. Although chemotherapy was started, her medical condition did not improve and she died a week later. Postmortem reevaluation of the pathological specimen confirmed her diagnosis as CD20⁺ PTCL-NOS. Although it is a rare disease entity, CD20⁺ T-cell lymphoma can demonstrate aggressive clinical behavior. [J Clin Exp Hematopathol 52(2) : 133-136, 2012]

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