Atypical lymphoproliferative disorders (LPDs) related with autoimmune disease (AID) show marked clinicopathological diversity, which are defined as three distinct clinicopathological subtypes such as those resembling Castleman disease (CD), atypical paracortical hyperplasia with lymphoid follicles (APHLF), and atypical lymphoplasmacytic and immunoblastic proliferation (ALPIB). We studied excisional biopsy specimens from 31 patients with atypical LPDs associated with systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and Sjögren syndrome (SjS). The lesions in these 31 cases were classified into 6 (19.4%) cases resembling CD, 14 (45.2%) cases of APHLF, and 11 (35.5%) cases of ALPIB. Five cases (83.3%) resembling CD were in the active stage with systemic symptoms and multicentric lymphadenopathy. Thirteen cases (92.9%) of APHLF showed systemic symptoms, multicentric lymphadenopathy and abnormal laboratory findings. Histologic findings for cases resembling CD were rare in patients with RA and SjS. In AID patients, histologic findings for cases resembling CD or APHLF findings correlated with disease activity and multicentric lymphadenopathy. Six cases (54.5%) of ALPIB were in the active phase with systemic symptoms and multicentric lymphadenopathy. ALPIB tended to be unrelated to AID activity, especially in the majority of patients with no abnormal laboratory findings. Atypical LPDs associated with AID is a group of diseases that may be overdiagnosed and overtreated. The diagnosis of atypical LPDs associated with AID requires an understanding of the histological findings as well as a comprehensive assessment of the presence of systemic symptoms, the distribution of lymphadenopathy, and abnormal laboratory findings.

Diffuse large B-cell lymphoma (DLBCL) and peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) are the most common subtypes of mature B cell neoplasm and T/NK cell lymphoma, respectively. They share a commonality in that they are, by definition, highly heterogeneous populations. Recent studies are revealing more about the heterogeneity of these diseases, and at the same time, there is an active debate on how to stratify these heterogeneous diseases and make them useful in clinical practice. The various immune cells and non-cellular components surrounding lymphoma cells, i.e., the lymphoma microenvironment, have been the subject of intense research since the late 2000s, and much knowledge has been accumulated over the past decade. As a result, it has become clear that the lymphoma microenvironment, despite its paucity in tissues, significantly impacts the lymphoma pathogenesis and clinical behavior, such as its prognosis and response to therapy. In this article, we review the role of the lymphoma microenvironment in DLBCL and PTCL-NOS, with particular attention given to its impact on the prognosis and stratification.

Ibrutinib is approved in Japan for the treatment of chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) based on the results of global and domestic clinical studies. Following approval, we conducted an all-case post-marketing surveillance in Japanese patients with relapsed/refractory CLL/SLL newly initiated on ibrutinib treatment between May 2016−September 2017. Of the 323 patients enrolled, the safety and efficacy analysis sets comprised 289 and 205 patients, respectively. The overall response rate with ibrutinib treatment was 64.4%, and the estimated 52-week progression-free survival (PFS) and overall survival (OS) rates were 71.7 and 79.1%, respectively. No significant difference in the PFS rate was observed among patients with and without del(17p) (P = 0.160); however, PFS was significantly longer in patients who received 1 prior line of therapy versus >1 prior lines of therapy (P = 0.007). Adverse events occurred in 74.0% of patients, and typically occurred early (≤12 weeks) after ibrutinib initiation, followed by a decline in incidence thereafter. The overall rates of infection, bleeding, and arrhythmia were 22.5, 12.8, and 4.8%, respectively. Grade ≥3 bleeding events and atrial fibrillation occurred in 2.4% of patients each. The efficacy and safety profile of ibrutinib treatment in routine clinical practice was consistent with clinical trials and previously reported domestic data.

UMIN-CTR Clinical Trials Register ID: UMIN000021963.

Peripheral blood stem cell harvest (PBSCH) is a crucial procedure for autologous stem cell transplantation in patients with multiple myeloma. We herein report a retrospective study to verify the usefulness of bortezomib and high-dose cyclophosphamide therapy (Bor-HDCY) as a conditioning regimen for PBSCH. Thirty-three patients were evaluated. The median age at the first apheresis was 61 (interquartile range, 53–64) years old, and 18 (54.5%) patients were male. Bor-HDCY was performed in 15 patients, and HDCY was performed in 18. In the patients who underwent Bor-HDCY, the CD34⁺ cell count at the first apheresis was significantly higher than in the others (P<0.01), and the total CD34⁺ cell count also tended to be high (P=0.0933). In terms of apheresis days, two-thirds of the patients who underwent HDCY had two-day apheresis, whereas most who underwent Bor-HDCY had one-day apheresis. According to univariate analysis, Bor-HDCY (P<0.01), VRd (Bor, lenalidomide, and dexamethasone) as induction therapy (P=0.0529), and ≥VGPR before PBSCH (P=0.0767) were factors associated with a higher CD34⁺ cell count at first apheresis. Although multivariate analysis showed that there were no independently significant factors influencing the CD34⁺ cell count at the first apheresis, the stepwise selection method revealed that only the Bor-HDCY regimen remained in the final model (P<0.005). Bor-HDCY may be a useful conditioning regimen for increasing the CD34⁺ cell yield.

Vanishing bile duct syndrome (VBDS) is a rare hepatic disorder which leads to liver failure as a result of progressive destruction of the intrahepatic bile ducts. There are no treatment modalities for VBDS itself and severe hepatic dysfunction restricts the treatment of underlying diseases. We safely treated a case of classic Hodgkin lymphoma (HL) with VBDS using brentuximab vedotin (BV). The patient was treated with 5 cycles of reduced BV and a partial metabolic response was obtained. Moreover, a standard dose of BV for another 5 cycles was accomplished with minimal adverse events. Our experience indicates that BV could be a treatment option for classic HL with VBDS.

The introduction of lenalidomide has significantly improved clinical outcomes in myelodysplastic syndrome (MDS) with isolated interstitial deletion of the long arm of chromosome 5 (del(5q)) (5q– syndrome). These days, MDS with isolated del(5q) includes cases with one additional chromosome abnormality other than monosomy 7 or del(7q), and so we need a better way to monitor tumor cells in each patient than the clinical parameters used to date. An 82-year-old woman with MDS with isolated del(5q) was treated with lenalidomide daily for 21 days in a 4-week cycle. Fluorescence in situ hybridization with CSF1R located at 5q was applied to the peripheral blood samples. Because mature lymphocytes are not involved in the MDS clone, based on the nuclear morphology, polymorphonuclear cells (PMNs) and round-shaped nuclear cells (RSNs) were separately evaluated during treatment. After a single course of treatment, the number of PMNs with del(5q) decreased; by the end of the second course of treatment, both PMNs and RSNs with del(5q) had disappeared. The dynamics of 5q– PMNs is a simple but rapid and reliable indicator to confirm the effect of lenalidomide in MDS with del(5q).

ALK-positive anaplastic large cell lymphoma (ALK+ ALCL) has a favorable prognosis in general; however, some cases are resistant to chemotherapy, which leads to a poor clinical outcome. We herein report the case of a 32-year-old male with aggressive ALK+ ALCL who presented with hemorrhage from a large tumor in the duodenum and multiple tumors in the lungs, mediastinum, and peritoneal cavity. Although induction chemotherapy resulted in a marked reduction of the tumor lesions, premature progression with massive pulmonary infiltration and central nervous system invasion occurred immediately after the completion of chemotherapy. The patient was then promptly treated with brentuximab vedotin (BV) and high-dose methotrexate, which resulted in complete remission. Subsequently, he successfully underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) from an unrelated donor and has been healthy and did not relapse for more than 3 years after transplantation without any additional therapy. Allo-HSCT may be a promising treatment option for ALK+ ALCL due to its graft-versus-lymphoma effect. In addition, molecular targeting agents, such as BV, may be promising as a bridging therapy before allo-HSCT to achieve disease remission.

Intestinal T/NK-cell lymphomas include enteropathy-associated T-cell lymphoma (EATL), monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), indolent T-cell lymphoproliferative disorders of the GI tract (ITCLPD), extranodal NK/T-cell lymphoma, nasal type (ENKTL), and intestinal T-cell lymphoma NOS (ITCL-NOS). Here we describe a case of surface CD3-negative MEITL. A 63-year-old Japanese female had a tumor located in the conglomerated ileum, which formed multiple mass lesions. The resected tissue showed a diffuse infiltration of monomorphic medium-sized lymphocytes with epitheliotropism. Flowcytometry using a fresh specimen of the tumor revealed positivity for CD7, CD8, CD38, and CD56, but not surface CD3. On immunohistochemistry, the tumor showed positivity for cytoplasmic CD3, CD8, CD56, TIA-1, Granzyme B, and perforin. EBER with in situ hybridization was negative. Moreover, H3K36me3, which is negative in MEITL with SETD2-mutation, was positive. This is an important case of MEITL due to its oncogenesis.

We report a case of donor-derived diffuse large B-cell lymphoma (DLBCL), which developed 5 years after stem cell transplantation from a human leukocyte antigen (HLA)-haploidentical donor for acute myeloid leukemia (AML). A 51-year-old male was diagnosed with AML with variant KMT2A translocation involving t(6;11)(q13;q23). After 12 cycles of azacitidine treatment, fluorescence in situ hybridization (FISH) for KMT2A split signal indicated that 94% of his bone marrow (BM) cells were positive. He underwent peripheral blood stem cell transplantation (PBSCT) from his HLA-haploidentical son. The preconditioning regimen consisted of fludarabine, busulfan, melphalan, and antithymocyte globulin (ATG). The graft-versus-host disease (GVHD) prophylaxis consisted of tacrolimus and short-term methotrexate. On day 28, KMT2A FISH analysis indicated that he had achieved a complete response (CR). He continued to receive tacrolimus for the limited type of cutaneous chronic GVHD. Five years after the transplantation, positron emission tomography/computed tomography (PET/CT) showed an abdominal tumor. The tumor was diagnosed as DLBCL without Epstein-Barr virus. BM aspiration revealed the infiltration of lymphoma cells with t(8;14)(q24;q32). Chimerism analysis showed that both the peripheral blood (PB) and abdominal lymphoma cells were of donor origin. After 4 cycles of salvage chemotherapy, PET/CT showed that a CR had been achieved. He underwent a second PBSCT from an HLA-identical unrelated donor. The preconditioning regimen and GVHD prophylaxis were the same as those for the first PBSCT without ATG. The patient’s PB revealed complete second donor-type chimerism, and the patient has maintained a CR since the second transplantation.

A 63-year-old man was diagnosed with Waldenström’s macroglobulinemia (WM). Six courses of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone) resulted in complete remission, but WM relapsed three years after R-CHOP. After six courses of BR (bendamustine, rituximab), the serum IgM level and CRP normalized. Four years after BR, the patient presented with muscle weakness, sensory disturbance, and myoclonus of lower limbs. T2-weighted magnetic resonance imaging (MRI) showed areas of signal hyperintensity with contrast enhancement in the right temporal and parietal lobes in brain parenchyma, medulla, bilateral basal ganglia, white matter of occipital lobe, and thoracic spinal cord at the Th2–11 levels. Open brain biopsy revealed diffuse proliferation of small lymphocytes and plasmacytoid lymphocytes on the brain surface and around cerebral blood vessels, resulting in a diagnosis of Bing-Neel syndrome (BNS). Two courses of R-MPV (rituximab, methotrexate, procarbazine, and vincristine) resulted in progressive disease, but the neurological symptoms and MRI findings improved following craniospinal irradiation of 30.6 Gy. Three years after craniospinal irradiation, T2-weighted MRI showed recurrence of BNS with progression of myoclonus of lower limbs and IgM elevation. Tirabrutinib was started for the second recurrence of WM and progression of BNS. Two months after the initiation of treatment with tirabrutinib, the myoclonus of lower limbs disappeared and the MRI findings showed improvement. Serum IgM levels decreased and no adverse events were observed. Tirabrutinib shows promise as a therapeutic option for relapsed BNS.