Remission of Congenital Multi-system Type Langerhans Cell Histiocytosis with Chemotherapy

Patients with multi-system (MS)-type langerhans cell histiocytosis (LCH) show poor outcomes, especially congenital MS LCH cases were shown in high mortality rate. We experienced a congenital case of MS LCH with high risk organs, who needed intensive respiratory support after birth. Even though intensive chemotherapy was discontinued, this patient’s lung LCH lesions gradually became reduced and his respiratory condition recovered; therefore, we restarted and completed maintenance chemotherapy. The patient maintained complete remission for more than 4 years after the end of chemotherapy. Our case suggests that congenital MS LCH even with severe organ involvement can be treated successfully with chemotherapy

PAX5 alterations in an infant case of KMT2A-rearranged leukemia with lineage switch

Lineage switch is a rare event at leukemic relapse. While mostly known to occur in KMT2A-rearranged infant leukemia, the underlying mechanism is yet to be depicted. This case report describes a female infant who achieved remission of KMT2A-MLLT3-rearranged acute monocytic leukemia, but 6 months thereafter, relapsed as KMT2A-MLLT3-rearranged acute lymphocytic leukemia. Whole exome sequencing of the bone marrow obtained pre-post lineage switch revealed two somatic mutations of PAX5 in the relapse sample. These two PAX5 alterations were suggested to be loss of function, thus to have played the driver role in the lineage switch from acute monocytic leukemia to acute lymphocytic leukemia

A Boy Safely Treated with Tyrosine Kinase Inhibitors for Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia with Osteolysis

A three-year-old boy with Philadelphia chromosome-positive B-cell precursor acute lymphoblastic leukemia (Ph+ALL) presented with an osteolytic lesion in his right upper arm. Tyrosine kinase inhibitors (TKIs) such as imatinib and dasatinib are an essential component throughout the course of treatment for Ph+ALL. However, TKIs are reported to affect the bone metabolism. In the treatment course of the current patient, the osteolytic lesion quickly improved despite the continuous use of TKIs, even during the concomitant use of corticosteroids. This suggests that TKIs can be safely given with concomitant corticosteroids to children with Ph+ALL, even when osteolytic lesions are present

Three Cases of Down Syndrome with Transient Abnormal Myelopoiesis who Underwent Liver Biopsy before Induction of Low-Dose Cytarabine

Among patients with transient abnormal myelopoiesis (TAM) associated with Down syndrome, approximately 20% die within 6 months from multiorgan failure, especially liver fibrosis. We experienced three children with TAM who had low white blood cell counts but increased bilirubin levels. Here, we discuss the detailed clinical courses of these patients, including the pathological findings of liver biopsies. Our cases, together with previous literature, suggest that liver biopsy can be performed safely and provides useful information, especially regarding disease activities, and that low-dose cytarabine is a reasonable option to prevent early death in TAM patients with liver dysfunction