Transmission electron microscopy revealed circular virus particles of approximately 25 nm in diameter in the cytoplasm of the villous epithelial cells of the lower small intestine. Histopathological examination did not reveal any abnormalities, such as atrophy, in the intestinal villi. Our results suggest that MuAstV proliferates in the villous epithelial cells of the lower small intestine and has weak pathogenicity.We report the case of a 79-year-old man with chronic lymphocytic leukemia (CLL) with IgM-kappa type monoclonal gammopathy according to immunophenotypes and a negative result for MYD88 L265P mutation of leukemic cells. Abnormal lymphocytes and IgM increased under observation, and he experienced paresthesia. The diagnosis of IgM-type M protein associated peripheral neuropathy was confirmed by nerve conduction test, and negativity of myelin-associated glycoprotein and glycolipid antibodies. He was placed on intravenous immunoglobulin (IVIg) in combination with ibrutinib. His symptoms dramatically subsided and did not recur. Treatment with IVIg and ibrutinib may be useful for the rare complication of peripheral neuropathy with CLL.Acquired hypofibrinogenemia is observed in patients with severe liver disease, disseminated intravascular coagulation, and high-volume perioperative fluid replacement. In lymphoblastic leukemia, hypofibrinogenemia is most frequently caused by the administration of L-asparaginase. Here we report the cases of two patients with acquired hypofibrinogenemia that occurred during steroid-containing chemotherapy treatment against lymphoblastic blast crisis of chronic myeloid leukemia in the first case and acute lymphoblastic leukemia in the second case. Administration of steroids repeatedly and promptly caused hypofibrinogenemia, irrespective of the products (prednisolone, dexamethasone, or methylprednisolone) or routes (oral or intravenous) that were used. Monitoring of the fibrinogen levels, especially during the first course of steroid therapy, would be useful for early diagnosis.A 67-year-old man with multiple myeloma had been treated with carfilzomib, lenalidomide, and dexamethasone (KRd) therapy. During the second course, he developed dyspnea, which gradually worsened. After admission, gastrointestinal losses of magnesium were confirmed, and intravenous magnesium was administered, which consequently improved his symptoms. Although KRd therapy was resumed, hypomagnesemia was recurring. Therefore, carfilzomib was replaced with ixazomib, which improved the patient's hypomagnesemia. The major causes of hypomagnesemia are gastrointestinal and renal losses; our case appeared to have gastrointestinal losses of magnesium and was successfully treated by discontinuing carfilzomib. Hypomagnesemia should be considered in patients receiving carfilzomib; furthermore, clinicians should consider discontinuing carfilzomib as its treatment.Acquired hemophilia A (AHA) is a disease that causes severe bleeding with the appearance of an inhibitor (INH) against blood coagulation factor VIII (FVIII). The prevalence of this condition is low; it occurs in only one in one to four million people per year; however, the number of diagnosed cases has increased in recent years owing to the greater awareness of the disease. It is noteworthy that this is a hemorrhagic disease that suddenly develops in the elderly. AHA treatment is divided into hemostatic treatment for bleeding and immunosuppressive therapy (IST) for removing FVIII-INH. As long as FVIII-INH remains, there is a risk of fatal bleeding; therefore, it is desirable to start IST soon after diagnosis. However, the use of immunosuppressive drugs for the elderly is often challenging due to concerns about adverse events, such as infectious diseases that have a considerable impact on prognosis. Ten years after the end of IST, we managed the case of a patient with AHA who had a relapse of FVIII-INH at the age of 84 years. In this case, relapse was detected early when there was no bleeding symptom, and remission was rapidly achieved with a small amount of IST without any adverse effects. There are few reports on AHA relapse; we believe that the present report will contribute meaningfully to the literature on this subject and would be useful when considering the long-term management of AHA.We report the case of a 26-year-old male patient with chronic myelogenous leukemia in the chronic phase with the e13a3 (b2a3) variant of BCR-ABL1 fusion. Despite the presence of Philadelphia chromosome and fluorescence in situ hybridization-detectable BCR-ABL1 fusion signals, quantitative measurement of BCR-ABL1 on the ABL1 using a reverse primer in exon 2 of ABL1 failed to detect the fusion transcripts. PCR direct sequencing analysis with a sense primer for exon 13 of BCR and an antisense primer for exon 3 of ABL1 revealed the e13a3 variant of BCR-ABL1 fusion. MG132 The variant fusion transcript level was successfully monitored by the TaqMan assay using a forward primer and probe both in exon 13 of BCR and a reverse primer in exon 3 of ABL1. The patient responded extremely well to imatinib treatment, similar to previously reported e13a3 cases. The patient achieved a molecular response (undetectable e13a3 transcripts) after 12 months of treatment.Acquired thrombotic thrombocytopenic purpura (aTTP) is a life-threatening systemic thrombotic microangiopathy characterized by the presence of anti-ADAMTS13 antibodies (inhibitor). Here we report the case of a patient with refractory aTTP successfully treated with cyclosporine. A 69-year-old man presenting with hematuria and petechiae was referred to our hospital; he was disoriented and febrile. Laboratory results revealed Coombs-negative hemolytic anemia, thrombocytopenia, and renal failure. Undetectable ADAMTS13 activity and presence of anti-ADAMTS13 antibodies (inhibitor) confirmed the diagnosis of aTTP. Despite performing plasma exchange and administering prednisolone and rituximab (375 mg/m2), we were unable to restore his platelet counts to the normal level. Therefore, he was treated with cyclophosphamide (500 mg/bodyweight), vincristine (1.4 mg/m2), bortezomib (1.3 mg/m2), and cyclosporine (2.5 mg/kg). After the cyclosporine therapy, his platelet counts gradually normalized. Continuous cyclosporine maintenance therapy led to complete disappearance of the inhibitor.