Tyrosine Kinase Inhibitor-induced Cerebrovascular Occlusion Presenting with Moyamoya Disease-like Stenosis of the Circle of Willis.

Vascular occlusive events are notable adverse effects of tyrosine kinase inhibitors (TKIs), which are promising treatments for chronic myeloid leukemia (CML). We herein report the case of a patient with CML who developed cerebrovascular occlusion of the circle of Willis during TKI treatment. Our patient did not meet the diagnostic criteria for moyamoya disease due to the insignificant development of moyamoya vessels. The lack of moyamoya vessel development may be explained by the suppression of tyrosine kinases that are responsible for angiogenesis. Cerebrovascular occlusion of the circle of Willis, without significant development of moyamoya vessels, may be an important phenotype of TKI-associated vasculopathy.

[Delayed diagnosis of hydroa vacciniforme-like lymphoproliferative disorder in a patient with skin rashes].

Chronic active Epstein-Barr virus (CAEBV) infection is characterized by persistent EBV infection and can lead to fatal conditions such as hemophagocytic syndrome and malignant lymphoma through the clonal expansion of EBV-infected T or natural killer (NK) cells. Hydroa vacciniforme lymphoproliferative disorder (HV) and hypersensitivity to mosquito bites (HMB) have been identified as skin diseases in EBV-associated T- or NK-cell lymphoproliferative diseases. We present the case of a 33-year-old man. The patient had frequent episodes of a facial rash for three years before he visited our hospital, he visited several dermatologists but did not receive a diagnosis of HV. He was referred to the hematology department of our hospital for assessment of atypical lymphocytes in peripheral blood. Based on routine blood and bone marrow test we were unable to diagnose HV. However, when the patient's liver function deteriorated six months later, we considered the possibility of HV after reevaluating the skin rash. After performing EBV-related tests, we were able to definitively diagnose CAEBV with HV. It is crucial to be able to connect clinical observations to EBV-related tests when diagnosing CAEBV. Hematologists must be knowledgeable of the EBV-associated skin conditions of HV and HMB.

Multilineage Lymphoblastic Lymphoma as an Initial Presentation of Mixed Phenotype Acute Leukemia.

Mixed phenotype acute leukemia (MPAL) is characterized by leukemic blasts that express markers of multiple lineages. Compared with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL), MPAL is considered to have a poor treatment outcome. We report a case of MPAL T/myeloid not otherwise specified that was initially presented as multilineage lymphoblastic lymphoma and subsequently developed into leukemic MPAL. An acute lymphoblastic leukemia-based treatment regimen was ineffective, but azacitidine and venetoclax therapy resulted in hematological complete remission. Our case suggests that multilineage lymphoblastic lymphoma should be considered to be the same disease as MPAL, albeit with different clinical presentations. Optimal treatment for MPAL has not been established yet, but azacitidine and venetoclax therapy may be a potential approach.