A 66-year-old man was diagnosed with symptomatic IgG-λ multiple myeloma based on the presence of anemia, thrombocytopenia, renal dysfunction, and a tumor on the right sixth rib. Bone marrow aspiration yielded a dry tap and biopsy revealed myelofibrosis grade 2. Partial response was achieved with Bd (bortezomib and dexamethasone) and VRd (bortezomib, lenalidomide, and dexamethasone). The patient received autologous stem cell transplantation, but the myeloma relapsed 3 months later, and liver tumors developed as well. DKd (daratumumab, carfilzomib, and dexamethasone) was administered, but the patient died due to disease progression. Autopsy revealed multiple extramedullary lesions in the liver, spleen, gallbladder, adrenal glands, kidneys, and multiple lymph nodes, as well as ascites.

An 18-year-old man underwent allogenic bone marrow transplantation (BMT) for Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL). Ph+ALL relapsed 3 months after the first BMT, and the patient underwent a second BMT. However, Ph+ALL relapsed 4 months after the second BMT, and he received a haploidentical peripheral blood stem cell transplantation (haplo-PBSCT) from his father. Molecular complete remission was confirmed 29 days after haplo-PBSCT. However, the patient needed dialysis for end-stage renal disease due to thrombotic microangiopathy 3 years and 2 months after haplo-PBSCT. He received a kidney transplantation from his father 7 years and 10 months after haplo-PBSCT, and got off dialysis after the kidney transplantation. Immunosuppressive therapy with methylprednisolone, tacrolimus, and mycophenolate mofetil was started for kidney transplantation, but the dose of immunosuppressive agents was reduced successfully without rejection soon after kidney transplantation. The patient has maintained long-term remission since the haplo-PBSCT, and his kidney function was restored by the kidney transplantation from his father.

A 24-year-old man was found to have an ileocecal ulcer by colonoscopy. A pathological diagnosis of diffuse large B-cell lymphoma (DLBCL) with diffuse positive reaction of Epstein-Barr encoding region (EBER) by in situ hybridization was made based on analysis of the specimen. Acquired immunodeficiency syndrome (AIDS) complicated by pneumocystis jirovecii pneumonia was also diagnosed. As no other significant lymphomatous lesions were identified by further examination, a clinical diagnosis of EBV-positive mucocutaneous ulcer (EBVMCU) was made. Rather than performing systemic chemotherapy, the lesion was closely monitored and antiretroviral therapy (ART) for AIDS was started with the hope of treating the lesion through immune reconstitution. The lesion had completely disappeared by day 79 after starting ART, and has not recurred for over 3 years. EBVMCU is known to develop secondary to various immunosuppressive states including AIDS. Here we report a rare case of EBVMCU detected at diagnosis of AIDS that entered complete remission after immune reconstitution by ART.

Aggressive types of adult T-cell leukemia-lymphoma (ATL), namely, the acute type, lymphoma type, and chronic type with poor prognostic factors, have a poor prognosis. Although allogeneic hematopoietic stem cell transplantation (HSCT) may improve prognosis, relapse is common. In June 2021, tucidinostat was approved for relapsed or refractory ATL in Japan. We report a case of a 62-year-old man with relapsed ATL after allogeneic HSCT. In March 2017, he was diagnosed with ATL (acute type) and received two courses of mLSG-15 therapy. ATL cells reappeared in his peripheral blood, so he underwent allogeneic bone marrow transplantation in September 2017. In June 2021, his soluble interleukin-2 receptor (sIL-2R) level increased, and he began experiencing sensory abnormalities in his face and legs. In September, he developed respiratory failure and was diagnosed with relapse of ATL. He was again treated with mLSG-15. His sIL-2R normalized and the sensory abnormalities decreased, but sIL-2R rose again in February 2022. After tucidinostat treatment was initiated, sIL-2R normalized and the patient’s general condition improved. Tucidinostat shows promise as an effective treatment for ATL that has relapsed after allogeneic HSCT.

Immune checkpoint inhibitor (ICI)-induced thrombocytopenias are rare immune-related adverse events (irAE), but ICI-related thrombotic thrombocytopenic purpura (TTP) is extremely rare. A 79-year-old woman with non-small cell lung cancer received maintenance therapy with the anti-human PD-L1 monoclonal antibody durvalumab. Four weeks after the last infusion, she developed overt TTP. Remission was achieved by plasma exchange and prednisolone, and the patient has now been recurrence-free for over 12 months. To our knowledge, this is the first report of TTP occurring as an irAE of durvalumab.

A 47-year-old woman presented with subcutaneous hemorrhage. Blood tests revealed leukoerythroblastosis, anemia, and thrombocytopenia. Bone marrow biopsy led to a diagnosis of primary myelofibrosis (aaDIPSS, DIPSS-plus: intermediate-II risk). JAK2, CALR, and MPL mutations were not detected in peripheral blood, but targeted sequencing of bone marrow specimens revealed a double mutation (Q157R, S34F) in U2AF1. Allo-PBSCT was performed using an HLA-matched related donor, and post-transplantation bone marrow examination showed complete donor chimerism on day 55. Two years after allogeneic transplantation, the patient remains relapse-free. Although U2AF1 gene abnormality is known as a poor prognostic factor in primary myelofibrosis, this patient had a favorable long-term prognosis due to prompt transplantation therapy. This case highlights the importance of detailed gene mutation analysis in patients with triple-negative MF.

A 64-year-old woman presented with fine motor impairment in both hands. MRI revealed a contrast-enhanced lesion in the medulla oblongata. Lymphoid cells with abnormal blebs were observed and a CD4⁺/CD8⁺ double positive (DP) T cell population was detected by flow cytometry (FCM) in the bone marrow (BM) and the peripheral blood (PB). CLEC16A::IL2 fusion gene was identified by whole exome sequencing with DNA prepared from DP T cells. Clonal rearrangement of the T-cell receptor gene and expression of TCL1A protein were detected. This led to a diagnosis of T-cell prolymphocytic leukemia (T-PLL) with central nervous system (CNS) infiltration. Abnormal cells in BM and PB became undetectable on microscopy and FCM, and the CNS lesion disappeared on MRI after second-line therapy with alemtuzumab. Meanwhile, the CLEC16A::IL2 fusion mRNA remained detectable in PB. Allogeneic hematopoietic stem-cell transplantation was performed, and the fusion mRNA has now been undetectable for more than 5 years since transplantation. This is the first report of a T-PLL case with a CLEC16A::IL2 fusion gene.

The patient was a 21-year-old man who had been diagnosed with Crohn's disease and received infliximab and azathioprine six years earlier. He was admitted with fever and fatigue. Peripheral blood examination showed LDH 2,473 U/l and thrombocytopenia, and contrast-enhanced computed tomography (CT) showed hepatosplenomegaly. Bone marrow biopsy and liver biopsy showed CD4+CD56+TCRγδ＋CD8⁻ atypical cells, leading to a diagnosis of hepatosplenic T-cell lymphoma (HSTCL). The patient was refractory to CHOP and DA-EPOCH, and therefore received cord blood transplantation with myeloablative conditioning. CT showed reduced in hepatosplenomegaly and peripheral blood examination showed LDH 165 U/l and plt 180,000/µl, so the patient was discharged on day117. HSTCL is a tumor of immature γδT cells with a Vδ1 mutation in the spleen, and immunodeficiency has been implicated in its pathogenesis. Patients with inflammatory bowel disease treated with azathioprine are known to have an increased risk of lymphoproliferative disease. In this case, use of immunosuppressive drugs for Crohn's disease may have caused malignant transformation of γδ cells in the intestinal epithelium. Although the patient was refractory to chemotherapy, he was able to achieve remission with early cord blood transplantation and long-term survival is expected.

T-lymphoblastic leukemia/lymphoma (T-ALL/LBL) has a poor prognosis. Nelarabine has recently shown relatively good results in patients with relapsed or refractory T-ALL/LBL, but requires careful monitoring for neurological complications. A 50-year-old man with early recurrence of T-LBL after allogenic peripheral blood stem cell transplantation received nelarabine monotherapy and achieved complete remission after 1 cycle. He then received umbilical cord blood transplantation, and experienced sustained disturbance of consciousness. He later died of multiple organ failure, and autopsy suggested that nelarabine-induced leukoencephalopathy had caused the disturbance of consciousness. This case suggests that physicians should carefully monitor patients for neurological complications and consider imaging follow-up and consultation with a neurologist.