Histiocytic sarcoma (HS) is an extremely rare malignant neoplasm showing morphologic and immunophenotypic evidence of histiocytic differentiation. The vast majority of previously reported HSs are now generally recognized to be misdiagnosed examples of non-Hodgkin lymphomas, predominantly diffuse large B-cell lymphoma or anaplastic large cell lymphoma. The recognition of such tumors parallels the development and widespread use of immunohistochemical techniques, along with the development of molecular genetic methods to detect immunoglobulin (IG) or T-cell receptor (TCR) gene rearrangement. The 2001 World Health Organization (WHO) definition of HS requires the absence of clonal B/T-cell receptor gene rearrangements. However, the 2008 WHO classification no longer strictly requires the absence of clonal immunoglobulin heavy chain (IGH) or TCR gene rearrangement for the diagnosis of HS. Recent studies demonstrated that HSs that occur subsequent to or concurrent with B- or T-lymphoblastic lymphoma/leukemia or mature B-cell neoplasms generally show clonal IgH and/or TCR gene rearrangement. These findings suggest the possibility of transdifferentiation of the two otherwise morphologically and immunohistochemically distinctive neoplasms. In addition, a recent study suggested clonal IG gene rearrangements may be detected at a high frequency in sporadic HS, indicating that a large subset of sporadic HSs may inherit the B-lymphocyte genotype. These findings provide new insights into the pathogenesis of HS, although the etiology of HS is still unknown. HS is a diagnosis of exclusion. It is necessary to rule out other diseases that could be misdiagnosed as HS with extensive immunophenotypical analysis before diagnosing HS. [J Clin Exp Hematop 53(1): 1-8, 2013]

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Thymic carcinoma (TC) is often very difficult to distinguish from type B3 thymoma and lung squamous cell carcinoma (L-SCC) involving the anterior mediastinum. The present study evaluated the usefulness of immunohistochemical markers including c-Kit, CD5, glucose transporter-1 (GLUT-1), claudin-1 (CLDN-1), thymoproteasome β5t, p53 and Ki-67 (MIB-1) and thymic cortical environmental marker cells, cortical thymocytes (c-Thy) and thymic cortical dendritic macrophages (TCDMs) in distinguishing thymic carcinoma (TC) from type B3 thymoma or lung squamous cell carcinoma (L-SCC) using 17 cases of type B3 thymoma, 18 cases of TC and 12 cases of L-SCC. The results indicated that c-Kit and CD5 are very useful markers for TC, while GLUT-1, CLDN-1, p53 and Ki-67 are not. Thymic cortical microenvironmental marker cells, especially TCDMs, and thymic cortical epithelial cell-marker β5t are also useful for distinguishing TC from type B3 thymoma. Although none of these markers are adequate for making a distinction when used alone, the plural use of c-Kit, CD5, β5t thymic cortical environmental marker cells, c-Thys and TCDMs may therefore lead to a correct distinction between TC and type B3 thymoma or L-SCC. [J Clin Exp Hematop 53(1) : 9-19, 2013]

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A 56-year-old man developed epistaxis, hoarseness, and swelling of a finger in March 2010. On the basis of biopsies of the masses in the pharynx and finger, he was diagnosed with extramedullary plasmablastic plasmacytoma, with somewhat immature CD45⁺, MPC-1^-, and CD49e^-. CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone) and VCAP (vincristine, cyclophosphamide, doxorubicin, and prednisolone) therapy was ineffective, but combination therapy with thalidomide and dexamethasone was highly effective. Thalidomide monotherapy successfully maintained partial remission for approximately 7 months. A mass appeared in the right neck in February 2011, and a biopsy confirmed recurrence. Changes to CD45 negativity and MPC-1 partial positivity were seen, while CD49e negativity persisted, suggesting that the plasmablastic plasmacytoma had reverted to a more immature state. Bortezomib therapy was started in March 2011 and was effective. However, during the second round of treatment, the patient developed acute lung injury, which was improved by steroid pulse therapy. After the discontinuation of bortezomib, the extramedullary mass increased rapidly, and the patient died of multiple organ failure. An autopsy showed that plasmablastic plasmacytomas had infiltrated into multiple organs. Extramedullary plasmacytomas and those that revert to an immature state are associated with a poor prognosis, so further treatment improvements are needed in the future. [J Clin Exp Hematop 53(1): 21-28, 2013]

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Waldenström macroglobulinemia and multiple myeloma are mature B-cell neoplasms deriving from post-germinal cells at different stages of differentiation. The simultaneous presentation of Waldenström macroglobulinemia and multiple myeloma in the same patient is a very rare phenomenon and, so far, only two cases have been described. We report the case of a 75-year Caucasian female patient, with a silent clinical history, who presented with anemia and two different monoclonal proteins (IgMκ and IgGκ). The trephine biopsy showed the presence of a dual population, represented by small lymphoplasmacytoid cells and by plasma cells, which infiltrated the bone marrow with a clearly different pattern. Both immunohistochemistry and flow cytometry demonstrated the biclonal origin such neoplastic cells, since lymphoplasmacytoid cells resulted IgMκ while plasma cells were IgGκ. This biclonal pattern was further confirmed by the demonstration of a different IgH gene rearrangement of the two neoplasms. The patient was treated with bortezomib, dexamethasone and rituximab, achieving partial remission of both Waldenström macroglobulinemia and multiple myeloma. After a 30-month follow-up, she is in stable disease. Multiple myeloma has been described in association with other indolent B-cell neoplasms, mostly chronic lymphocytic leukemia, while Waldenström macroglobulinemia can be followed by diffuse large B-cell lymphoma in some instances, after chemotherapy. The association of Waldenström macroglobulinemia and multiple myeloma seems to be very rare. Our study shows that an integrated diagnostic work-up is very useful in such cases, with an interesting role for flow cytometry. [J Clin Exp Hematop 53(1): 29-36, 2013]

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A 67-year-old man was diagnosed with CD56⁺ angioimmunoblastic T cell lymphoma (AITL), which was associated with autoimmune thrombocytopenic purpura (ATP) and autoimmune hemolytic anemia (AIHA) (Evans syndrome). The ATP was refractory to Helicobacter pylori eradication therapy and steroid. Complete remission (CR) of both AITL and AIHA was achieved with THP-COP chemotherapy (pirarubicin, cyclophosphamide, vincristine, and prednisolone), but ATP was not improved promptly. AITL associated with ATP has been reported in only 14 cases. The present case was not related to the serum interleukin-6 levels, suggesting the possibility of an association with other factors. This case is the first report of Evans syndrome associated with AITL. The AITL relapsed 2 months after CR. The AITL tumor were CD56-positive at initial diagnosis and CD56-negative at relapse, and showed complex additional chromosomal abnormalities, and the morphological characteristics of blast cells. CD56⁺ AITL are rare, although CD56 expression has not been investigated in many cases ; our observations suggest that CD56 expression and its significance in AITL should be investigated in the future. There has been only one other case of CD56⁺ AITL, the patient died 4 months after the diagnosis. Our patient reported showed early relapse, central nervous system infiltration and was refractory to treatment, suggesting that CD56 positivity may be a poor prognostic marker in patients with AITL. [J Clin Exp Hematop 53(1): 37-47, 2013]

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Ocular adnexal lymphoma may involve the eyelids, conjunctiva, orbital tissue, or lacrimal structures. The majority are non-Hodgkin's B-cell lymphomas of mucosa-associated lymphoid tissue (MALT) lymphoma type. Follicular lymphomas represent a small percentage of ocular adnexa lymphomas, particularly in Japan. We report a 68-year-old female patient who presented with a salmon pink patch-like lesion of the left conjunctiva, suspected of being (MALT) lymphoma. However, histologic and immunohistologic examinations were consistent with follicular lymphoma. This case demonstrates the importance of considering such rare lymphomas when making a diagnosis of ocular adnexal lymphoid neoplasms. [J Clin Exp Hematop 53(1): 49-52, 2013]

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There are no reports on the effect of anti-allergic agents against IgG4-related disease. We herein report a case of IgG4-related dacryoadenitis that is believed to have regressed due to the administration of anti-allergic agents. A 57-year-old woman consulted us because of bilateral temporal upper eyelid swelling and induration. She had also been suffering from allergic rhinitis and allergic conjunctivitis for 20 years. We performed an incisional biopsy of the lesion. With respect to the pathology, extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue type was strongly suspected. On obtaining consent from the patient, follow-up alone was to be continued without radiation therapy. In addition to the observation of lacrimal gland lesions, the administration of epinastine hydrochloride at a dosage of 20 mg/day and 0.01% betamethasone eye drops twice a day to both eyes was commenced in order to treat both allergic rhinitis and allergic conjunctivitis. The lacrimal gland lesion decreased in size over time, becoming predominantly normal 7 years after the commencement of agent administration. We therefore re-examined the blood and pathology specimens. As a result, the serum IgG4 level was found to have increased to 540 mg/dl, while IgG4/IgG was 36.2%. The pathological diagnosis was revised to IgG4-related dacryoadenitis. The hypotheses of spontaneous remission and/or the effect of epinastine hydrochloride administration can be proposed regarding the mechanism by which the lacrimal gland lesion decreased in size. [J Clin Exp Hematop 53(1): 53-56, 2013]

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Recently, a unique clinicopathologic variant of multicentric Castleman's disease (MCD) has been identified in Japan. This disease is characterized by a constellation of symptoms, as listed in the title, and multiple lymphadenopathy of mild degree with a pathologic diagnosis of atypical CD, often posing diagnostic and therapeutic problems for pathologists and hematologists, respectively. These findings suggest that this disease represents a novel clinical entity belonging to systemic inflammatory disorders with a background of immunological abnormality beyond the ordinal spectrum of MCD. To define this disorder more clearly, Japanese participants presented clinicopathologic data at the Fukushima and Nagoya meetings. Many of the patients presented by the participants were significantly accompanied by a combination of thrombocytopenia, ascites (anasarca), pleural effusions, microcytic anemia, fever, myelofibrosis, renal dysfunction, and organomegaly (TAFRO). Multiple lymphadenopathies were generally of mild degree, less than 1.5 cm in diameter, and consistently featured the histopathology of mixed- or less hyaline vascular-type CD. Autoantibodies were often detected. However, this disease did not fulfill the diagnostic criteria for well-known autoimmune diseases including systemic lupus erythematosus. Castleman-Kojima disease and TAFRO syndrome (the favored clinical term) were proposed for this disease. The patients were sensitive to steroid and anti-interleukin-6 receptor antibody (tocilizumab), but some exhibited a deteriorated clinical course despite the treatment. The participants proposed a future nationwide survey and a Japanese consortium to facilitate further clinical and therapeutic studies of this novel disease. [J Clin Exp Hematop 53(1): 57-61, 2013]

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We report five cases that presented with high fever, anasarca, hepatosplenomegaly and severe thrombocytopenia with reticulin fibrosis of the bone marrow. The constellation of symptoms is not compatible with any known disease, and we had difficulty in diagnosis and treatment. The age distribution was from 47 to 56 years, and two men and three women were affected. Two patients needed hemodialysis because of renal dysfunction and oliguria with massive pleural effusion. Laboratory examinations showed normal immunoglobulin levels and no monoclonal protein. None of them showed diagnostic autoantibodies for any autoimmune diseases. Histological examination of the liver in three patients and spleen in two showed non-specific findings. Lymphadenopathy was tiny and lymph node biopsy was carried out in only one case. Histologically, paracortical hyperplasia with vascular proliferation and atrophic germinal centers resembling hyaline-vascular-type Castleman's disease or POEMS syndrome were detected. Without a definitive diagnosis, treatment was started with cyclophosphamide, hydroxydaunorubicin, vincristine and prednisolone (CHOP) regimen in one patient, semi-pulse therapy with methyl-predonisolone in three and cyclosporin A in three. Two patients achieved complete remission, two were steroid-dependent and the remaining one died of multiple organ failure. These findings suggest that this disease may be a novel clinical entity belonging to systemic inflammatory disorder with a background of immunological abnormality or a unique variant of multicentric Castleman's disease. [J Clin Exp Hematop 53(1): 63-68, 2013]

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Multicentric Castleman's disease (MCD) is a rare polyclonal lymphoproliferative disorder that manifests with lymphadenopathy and inflammatory symptoms. In order to clarify the clinical features and actual management of MCD in Japan, we analyzed 21 patients diagnosed with MCD and treated in Kyoto University Hospital between 2005 and 2012. There were 12 men and 9 women. The median age at disease onset was 46 years, and the median follow-up period was 98 months. Common symptoms included splenomegaly (13/20), renal dysfunction (11/21), interstitial pneumonia (7/21), pleural effusion and/or ascites (7/21), and thrombocytopenia (6/21). The results of the anti-human immunodeficiency virus antibody and human herpes virus-8 DNA tests in the blood were available in 13 and 5 cases, respectively, and no patient was positive for either. Among 12 patients treated with tocilizumab, an anti-interleukin-6 receptor antibody, 11 exhibited an improvement in MCD-related symptoms and 3 achieved complete resolution of all these symptoms. In 8 patients treated with tocilizumab for over 1 year, the mean Hb level increased from 7.4 to 12.2 g/dL while the mean serum C-reactive protein level decreased from 13.2 to 0.4 mg/dL. Three patients died during the observation period due to sepsis, secondary leukemia, or pancreatic cancer. The clinical courses of most cases were indolent; however, in some cases with pleural effusion, ascites, renal dysfunction, and/or thrombocytopenia, the disease manifestation was serious. A nationwide survey is required to further clarify the epidemiology, clinical features, and optimal treatment strategies of MCD in Japan. [J Clin Exp Hematop 53(1): 69-77, 2013]

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Multicentric Castleman's disease (MCD) is a polyclonal lymphoproliferative disorder that manifests as marked hyper-γ-globulinemia, severe inflammation, anemia, and thrombocytosis. Recently, Takai et al. reported a new disease concept, TAFRO syndrome, named from thrombocytopenia, anasarca, fever, reticulin fibrosis, and organomegaly. Furthermore, Kojima et al. reported Japanese MCD cases with effusion and thrombocytopenia (Castleman-Kojima disease). Here, we report two cases of MCD associated with marked pleural effusion, ascites, and thrombocytopenia, and discuss the independence of the TAFRO syndrome (Castleman-Kojima disease). Case 1: A 57-year-old woman had fever, anemia, anasarca, and some small cervical lymphadenopathy. Although she had been administered steroid therapy, and full-coverage antibiotics, her general condition, including fever, systemic inflammation, and anasarca, deteriorated steadily. We administered chemotherapy [CHOEP (cyclophosphamide, doxorubicin, vincristine, etoposide, and prednisolone) regimen], but despite a transient improvement, she died due to septic shock. Case 2: A 73-year-old man with a history of aplastic anemia and remission presented with fever, severe inflammation, and anasarca. Prednisolone was administered (15 mg daily), and his hyperinflammation once improved. Nevertheless, his general condition, including pleural effusion and ascites, worsened, and C-reactive protein and interleukin-6 levels showed marked increases. The patient died due to multiorgan failure. Cases of TAFRO syndrome (Castleman-Kojima disease) are still rare. Therefore, it is necessary to conduct multicenter clinical surveys including similar cases, such as ours, to reach a consensus regarding diagnostic criteria, therapeutic strategy, and pathophysiological etiology for this syndrome. [J Clin Exp Hematop 53(1): 79-85, 2013]

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Recently, atypical Castleman's disease (CD) was reported in Japan. This disease is considered as TAFRO syndrome or non-idiopathic plasmacytic lymphadenopathy (IPL), a constellation of clinical symptoms, namely, thrombocytopenia, anasarca, fever, reticulin fibrosis, and organomegaly without hyper-γ-globulinemia. Histopathologically, this disease is similar to hyaline vascular (HV)-type CD. Here, we present a 43-year-old Japanese woman meeting the clinical criteria of TAFRO syndrome who was successfully treated with combined corticosteroid therapy. She showed a rapidly progressive course of thrombocytopenia, systemic lymphadenopathy, fever, anasarca, and increase in acute inflammatory proteins without hyper-γ-globulinemia. Lymph node biopsy was performed and revealed HV-type CD without human herpes virus 8 infection, which was clinicopathologically compatible with non-IPL. The association of these atypical features with well-known multicentric Castleman's disease (MCD), namely, HV-type histology with systemic lymphadenopathy, marked thrombocytopenia even with a high level of interleukin-6, and increased acute inflammatory proteins without hyper-γ-globulinemia, suggests that TAFRO syndrome as presented in our case is a novel entity, which may have been diagnosed as MCD in the past. To define this novel entity more clearly and to demonstrate its etiology, further nationwide surveys of this syndrome and MCD are needed. [J Clin Exp Hematopathol 53(1) : 87-93, 2013]

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A 49-year-old woman with severe thrombocytopenia was admitted after an episode of syncope. She also had anemia, fever, pleural effusion and ascites, and multiple lymphadenopathies subsequently appeared. Her bone marrow showed increased megakaryocytes with mild fibrosis, whereas her lymph nodes lacked histologically specific findings. Her presentation was not consistent with multicentric Castleman's disease, angioimmunoblastic T-cell lymphoma, systemic lupus erhythematosus or any other well-recognized entities. Her clinical features were, however, thought to be compatible with TAFRO (thrombocytopenia, anasarca, fever, reticulin fibrosis, and organomegaly) syndrome. Corticosteroid therapy induced a partial remission of fever and systemic fluid retention, but thrombocytopenia persisted. After additional immunosuppressive therapy with cyclosporin A, her symptoms showed full resolution. [J Clin Exp Hematop 53(1) : 95-99, 2013]

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