Both interdigitating cell sarcoma (IDCS) and follicular dendritic cell sarcoma (FDCS) are rare neoplasms derived from dendritic cells in lymphoid organs. IDCS is defined as a neoplastic proliferation of spindle-shaped to ovoid cells with phenotypic features similar to those of IDCs. FDCS is a malignant neoplasm derived from FDCs that possess and present antigens to B cells in the follicular (germinal) centers of lymphoid organs. They often occur in lymph nodes, although they can also arise at extranodal sites. In this review, we have highlighted the morphological and immunohistochemical properties of these neoplasms, which could help in unequivocal and accurate diagnosis. [J Clin Exp Hematop 53(3) : 179-184, 2013]

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Molecularly-targeted therapy is a promising strategy for the treatment of cancer. Nuclear factor (NF)-κB is a transcription factor that is constitutively activated in various lymphoid malignancies and may therefore be a good therapeutic target. Lymphoid malignancies arise from different stages of normal lymphocyte differentiation and acquire distinct pathways for constitutive NF-κB activation. However, no NF-κB inhibitor has yet been successfully applied in clinical medicine. This review focuses on the concept of molecularly-targeted therapeutics with small molecule drugs, molecular mechanisms of constitutive NF-κB activation in lymphoid malignancies, and the development of NF-κB inhibitors. A future perspective regarding the development of NF-κB inhibitors is also included. [J Clin Exp Hematop 53(3) : 185-195, 2013]

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We evaluated the prognostic significance of the serum level of the soluble form of interleukin-2 receptorα (sIL-2Rα) and investigated its association with CD25 expression on tumor cells in diffuse large B-cell lymphoma (DLBCL). Three hundred and thirty-eight adult patients with newly diagnosed DLBCL were eligible for this retrospective study. 32.2% of patients were treated with CHOP-like regimen and 67.8% with R-CHOP-like regimen. CD25 expression on the surface of tumor cells was evaluated in 143 cases and its relationship with sIL-2Rα level was also investigated. Both overall survival (OS) and progression-free survival (PFS) were poorer in patients with higher sIL-2Rα, in both R-CHOP and CHOP groups. sIL-2Rα > 1,000 U/mL and performance status (PS) ≥ 2 were independently associated with poorer OS, and sIL-2Rα > 1,000 U/mL, age > 60 years, and ≥ 2 extranodal sites were independently associated with poorer PFS in the R-CHOP group. The sIL-2Rα level was higher in the CD25-positive group than in the CD25-negative group in stage 3 or 4 disease (p = 0.010). Multiple linear regression analysis showed CD25 expression to be independently correlated with sIL-2Rα levels. High sIL-2Rα is an important risk factor for survival in DLBCL treated with not only CHOP-like, but also R-CHOP-like regimens, regardless of the tumor's expression of CD25. [J Clin Exp Hematop 53(3) : 197-205, 2013]

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We report a patient with aggressive systemic mastocytosis (SM), who exhibited eosinophilia and unusual destructive bone lesions. A 43-year-old female was referred to our hospital because of a vertebral compression fracture, multiple lytic bone lesions, and eosinophilia in February 2011. A diagnosis of aggressive SM was made on the basis of abnormal mast cells in the bone marrow, high serum tryptase levels, and multiple lytic bone lesions including vertebral compression fractures. Polymerase chain reaction and subsequent sequencing of its products to identify mutations of c-kit yielded negative results and imatinib mesylate failed to improve the SM of the patient. She was then treated with interferon-α, with considerable improvement of the disease, although severe myelosuppression prevented the continued administration of a sufficient dose of this agent. In August 2011, the patient suddenly developed paraplegia of the lower extremities. Magnetic resonance imaging demonstrated epidural mass lesions at the levels from Th9 to Th11, compressing the spinal cord. Emergent laminectomy and subsequent irradiation of the tumors were performed without improvement of the paraplegia. Histopathologic examination of the epidural tumors, from samples obtained intraoperatively, confirmed the diagnosis of SM. She was further treated with dasatinib and then cladribine without obvious improvement, although the latter reduced the eosinophilia to some extent ; however, she died of sepsis in September 2011. [J Clin Exp Hematop 53(3) : 207-213, 2013]

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We report a rare case of non-Hodgkin lymphoma with mass lesions of skull vault and ileocecum. The patient was an 82-year-old Japanese woman who exhibited a painless subcutaneous scalp tumor in the right parietal region associated with no neurological abnormalities. Magnetic resonance imaging of the head demonstrated a mass in the skull vault with iso- to hypointense signals on both T1- and T2-weighted imaging. Biopsy of the mass revealed that the tumor comprised large cells that were immunoreactive for CD20 (L-26) and CD79a. Diffuse large B-cell lymphoma (DLBCL) was therefore diagnosed. Further investigation could not identify any other evidence of systemic lymphoma other than ileocecal lesions. She was treated by irradiation (45 Gy) of the mass on the parietal bone and with rituximab, pirarubicin, cyclophosphamide, and vincristine. The patient achieved complete remission after 3 cycles of systemic chemotherapy. As of 30 months after presentation, no signs of lymphoma have been found. [J Clin Exp Hematop 53(3) : 215-219, 2013]

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Neurolymphomatosis (NL) is a rare clinical entity defined as peripheral nervous system infiltration by lymphoma. The diagnosis is difficult and often elusive. Whole-body diffusion-weighted magnetic resonance imaging (DW MRI) was developed to enhance the detection of vaguely delineated tumors. Here, we describe the case of a 71-year-old male with secondary NL of diffuse large B-cell lymphoma (DLBCL) that was successfully detected by whole-body DW MRI. The patient was diagnosed with DLBCL extending from the ethmoidal sinus to the nasal cavity, orbital cavity, and anterior cranial fossa. Although he was administered R-THP-COP chemotherapy and the tumor remarkably decreased in size, he developed painful paresthesia and weakness in the left upper and bilateral lower extremities during treatment. Because lymphoma cells were detected in his spinal fluid, high-dose methotrexate (MTX) and weekly intrathecal MTX and cytarabine injections were administered. Test results for lymphoma cells in the spinal fluid became negative ; however, the neurological disorders progressed. Whole-body DW MRI was performed as whole-body screening and could localize NL at the left cervical and bilateral lumbar nerve roots. Both cervical spine plain MRI and enhanced computed tomography performed around the same time could not detect the cervical lesion. Our case report suggests that whole-body DW MRI is a useful diagnostic imaging procedure, especially as whole-body screening in facilities where PET/CT is not available. [J Clin Exp Hematop 53(3) : 221-226, 2013]

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A 47-year-old man was diagnosed with Philadelphia chromosome-positive chronic myeloid leukemia (CML) in October 2005. He could not receive treatment with imatinib mesylate due to his economic circumstances. He was consequently treated with hydroxyurea with partial hematological remission until June 2008. Although imatinib mesylate was started thereafter, the adherence to this treatment was poor because of his occupational circumstances. In September 2009, imatinib mesylate was switched to nilotinib, with a subsequent phase of acceleration of the disease, presumably due to his poor adherence to the treatment. Dasatinib was started in September 2010, with transient hematological response and final blastic crisis of the disease in January 2011, regardless of improved adherence. Blast cells showed immature monocytic morphology and were positive for α-naphtylbutyrate esterase staining. They also expressed surface CD14 and CD64 antigens. A diagnosis of rare monocytic crisis of CML was made. He was treated with low-dose nilotinib following cytoreduction with MEC (mitoxantrone, etoposide, and cytarabine) chemotherapy. Severe leucopenia without circulating leukemic cells continued for about 2 months with sustained hepatosplenomegaly, and he died of pneumonia in March 2012. Necropsy showed severe bone marrow hypoplasia with focal infiltration of mature leukemic cells and similar infiltration in the liver. [J Clin Exp Hematop 53(3) : 227-233, 2013]

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Granulocytic sarcoma is a rare disease that is rarely curable with conventional chemotherapy. This report describes a case of a patient with bulky granulocytic sarcoma of the retroperitoneum who was treated with high-dose chemotherapy and autologous peripheral blood stem cell transplantation without administering granulocyte colony-stimulating factor before stem cell collection. According to bone marrow assessment and imaging studies, the patient remained in complete remission at 5 years after transplantation. This case suggests that high-dose chemotherapy followed by autologous peripheral blood stem cell transplantation is a therapeutic option for granulocytic sarcoma. [J Clin Exp Hematop 53(3) : 235-239, 2013]

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Crystal-storing histiocytosis is a rare clinical entity characterized by an increase in the number of abnormal histiocytes accompanied by accumulation of crystallized immunoglobulins. We describe the case of an 80-year-old man who presented with crystal-storing histiocytosis of the lung 13 years after receiving a diagnosis of gastric non-Hodgkin lymphoma (NHL ; clinical stage, Lugano IA). After wedge resection of the left upper lobe, the histological findings showed crystal-storing histiocytosis with CD68⁺, some small to medium lymphoid cells with CD79a⁺ with κ^+(weekly) and λ^-, and some plasma cells with CD138⁺, and rearrangement of the immunoglobulin heavy chain. Based on the nonrecurrent gastric NHL, small B-cell population, and failure to detect the same clone by polymerase chain reaction analysis, our case was classified as pulmonary localized crystal-storing histiocytosis without underlying lymphoproliferative or plasma cell disorder. The findings of minor B-cell populations harboring a heavy chain rearrangement with slight light-chain restriction (κ > λ) may be related to the pathogenesis of crystallogenesis and crystal-storing histiocytosis. Moreover, surgical treatment may be an effective therapeutic option for solitary crystal-storing histiocytosis. [J Clin Exp Hematop 53(3) : 241-245, 2013]

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Bone marrow mononuclear cells from 93 patients with hematological malignancies after allogeneic hematopoietic stem cell transplantation (AHSCT) were analyzed using flow cytometry (FCM). The disease was acute myeloblastic leukemia (50 patients), acute lymphoblastic leukemia, and others. Conditioning was myeloablative (80 patients) or reduced intensity. The stem cell source was bone marrow (75 patients), peripheral blood stem cells, or cord blood. After AHSCT, granulocyte colony-stimulating factor was given to all patients. All patients showed engraftment of the donor cells. FCM was conducted on a median of 22 days after AHSCT. The gate was set around a granulocytic region consisting of immature granulocytes. The positivity rates of CD13, CD14, CD15, CD33, CD34, CD56, and HLA-DR in the cells were 59.9 ± 27.4%, 5.8 ± 8.8%, 98.3 ± 1.9%, 92.3 ± 12.4%, 2.6 ± 5.8%, 24.3 ± 16.7%, and 9.1 ± 6.6%, respectively. The greatest value of CD56 positivity was 73.1%. On the basis of CD56 expression, cases of more than 24% CD56 positivity were assigned to the CD56-high group (39 patients), while the rest were assigned to the CD56-low/negative group. There were no significant differences between the two groups in terms of disease status, sex, donor, hematopoietic stem cells, days of FCM analysis, or peripheral blood cell counts around the days of performing FCM. These results indicate that CD56 can be expressed in normal immature granulocytes at a variety of expression levels in regenerative bone marrow. Attention should be paid when evaluating aberrant antigen expression of CD56 in granulocytes. [J Clin Exp Hematop 53(3) : 247-250, 2013]

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