To clarify the clinicopathologic findings of idiopathic multicentric Castleman disease among Japanese, 28 cases were studied. Two variants were delineated by the clinicopathologic findings (1) idiopathic plasmacytic lymphadenopathy with polyclonal hyperimmunoglobulinemia (n = 18) and (2) nonidiopathic plasmacytic lymphadenopathy type (n= 10). Clinicopathologically, idiopathic plasmacytic lymphadenopathy was defined by the prominent polyclonal hyperimmunoglobulinemia, normal germinal centers, and sheet-like infiltration of plasma cells in the interfollicular area of the lymph node. Histologically, the nonidiopathic plasmacytic lymphadenopathy type was characterized by hyaline-vascular germinal centers of the lymph node lesion. In comparison with idiopathic plasmacytic lymphadenopathy, patients with nonidiopathic plasmacytic lymphadenopathy showed infrequent prominent polyclonal hyperimmunoglobulinemia and frequent association with autoimmune disease. However, there was no difference in the overall 5-year survival between the 2 subtypes. Compared with idiopathic multicentric Castleman disease in Western countries, the chronic course of the disease of idiopathic multicentric Castleman disease in Japan appears to be related to negativity for human herpesvirus 8 infection.

To clarify the clinicopathological findings of primary salivary gland lymphoma as defined by the World Health Organization (WHO) classification, 30 Japanese patients with this disease were studied. The male to female ratio was 1:1.7 and median patient age was 57 years. The parotid gland (n = 22) was involved most frequently, followed by the submandibular gland (n = 5) and minor salivary gland (n = 3). Twenty-four (80%) cases demonstrated Stage IE, whereas only six (20%) had Stage IIE-1. None of the 30 cases had "B" symptoms or a poor performance status. The 5-year overall survival of 31 cases was 96% and 5-year failure-free survival was 77%. Histologically, 15 cases were mucosa-associated lymphoid tissue (MALT) lymphoma, seven were follicular lymphoma (FL), and six were diffuse large B-cell lymphoma (DLBCL) + MALT lymphoma and only two were DLBCL without a MALT lymphoma component. MALT lymphoma is the most frequent type of primary salivary gland lymphoma. However, FL comprised 20% of primary salivary gland lymphoma. The majority of the primary salivary gland DLBCL appear to arise from MALT type lymphoma. When appropriate therapy for histologic subtype is used, outcome of the primary salivary gland B-cell lymphoma appears excellent whether histologically indolent or aggressive.

We present here seven cases of idiopathic multicentric Castleman's disease (MCD) showing effusion at the initial clinical presentation. This series includes a high proportion of middle-aged and elderly females (5/7). Various autoantibodies were detected in six cases. Anemia (Hb < 10 g/dl) was detected in four cases, leukocytosis (WBC > 10 × 10(9)/l) in three and thrombycytopenia (<100 × 10(9)/l) in five. Positivity for C-reactive protein or elevated erythrocyte sedimentation rate was recorded in all seven cases. Elevated serum IgG level (>2000 mg/dl) was recorded in only three cases. Elevated serum interleukin-6 level was recorded in all four cases examined. At the onset of disease, four cases were associated with idiopathic thrombocytic purpura. During the course of disease, one case each was diagnosed as systemic sclerosis + Sjögren's syndrome (SJS) and SJS. Histologically, five lesions exhibited a mixed type of Castleman's disease, and one case each exhibited a hyaline-vascular type and plasma cell type. The non-neoplastic nature of the B-lymphocytes was demonstrated by immunohistochemistry and polymerase chain reaction. There were no human herpes type-8 virus-positive cells in any of the seven lesions. Good responsiveness to glucocorticoid therapy has been seen in all six cases treated. From a therapeutic perspective, it is important to discriminate this subtype of MCD.

Atypical lymphoplasmacytic immunoblastic proliferation (ALPIB) is a rare lymphoproliferative disorder (LPD) associated with autoimmune disease (AID). To further clarify the clinicopathologic, immunohistological, and genotypic findings of ALPIB in lymph nodes associated with well-documented AIDs, 9 cases are presented. These 9 patients consisted of 4 patients with systemic lupus erythematosus, 3 patients with rheumatoid arthritis, and one case each with Sjögren's syndrome and dermatomyositis. All 9 patients were females aged from 25 to 71 years with a median age of 49 years. Four cases presented with lymphadenopathy as the initial manifestation. In 4 patients, immunosuppressive drugs were administered before the onset of lymph node lesion. However, none of the 9 patients received methotrexate therapy. The present 9 cases were characterized by : (i) prominent lymphoplasmacytic and B-immunoblastic infiltration ; (ii) absence of pronounced arborizing vascular proliferation ; (iii) absence of CD10 + "clear cells" ; (iv) presence of hyperplastic germinal center in 7 cases ; (v) immunohistochemistry, flow cytometry, and polymerase chain reaction demonstrated a reactive nature of the T-and B-lymphocytes ; and (vi) on in situ hybridization, there were no Epstein-Barr virus -infected lymphoid cells in any of the 9 cases. Overall 5-year survival of our patients was 83%. The combination of clinical, immunophenotypic, and genotypic findings indicated that the present 9 cases can be regarded as having an essentially benign reactive process. Finally, we emphasized that ALPIB should be added to the differential diagnostic problems of atypical LPDs, particularly lymph node lesions of IgG4-related diseases. 〔J Clin Exp Hematopathol 50(2) : 113-119, 2010〕

To clarify the clinicopathological findings of B-cell lymphoma associated with Sjögren's syndrome (SJS) among Japanese Patients, 15 individuals with this disease were studied. The patients, 14 females and one male, ranged in age from 41 to 73 years with a median age of 56 years. These lymphomas arose not only in the salivary gland (n=4) but also in other mucosal extranodal sites (n=5). Histologically, six cases were marginal zone B-cell lymphoma (MZBL) of the mucosa-associated lymphoid tissue (MALT) type, three cases were diffuse large B-cell lymphoma (DLBCL) + MALT type lymphoma, two cases were nodal MZBL and one case each was small lymphocytic lymphoma, Burkitt's lymphoma, CD10(+) DLBCL and DLBCL + nodal MZBL. Using in situ hybridization, numerous Epstein-Barr virus(+) tumor cells were detected only in the case of Burkitt lymphoma. There were no human-herpes type 8(+) tumor cells in any of the 15 cases. There was no API2-MALT1 fusion transcript in any of the eight cases examined. B-cell lymphoma associated with SJS also frequently affected extranodal organs in patients from Japan as well as from patients in Western countries. The majority of B-cell lymphomas in patients with SJS also appear to be low-grade MZBLs or high-grade lymphomas probably derived from MZBL both in Western countries and in Japan.