[Intestinal pneumatosis developed during the treatment of severe gastrointestinal graft-versus-host disease after cord blood transplantation].

A 62-year-old female developed stage4 gastrointestinal graft-versus-host disease (GVHD) on day 109 following an allogeneic cord blood transplant for relapsed refractory angioimmunoblastic T-cell lymphoma. GVHD went into remission 4 weeks after receiving the steroid (mPSL 1 mg/kg), but abdominal bloating started to emerge at the same time. A diagnosis of intestinal pneumatosis was made on day 158 after a CT scan revealed submucosal and serosal pneumatosis in the entire colon, and intestinal pneumatosis was identified as the cause. Fasting and reducing steroid use have helped. the abdominal symptoms, and the pneumatosis disappeared on day 175. No more flare-ups occurred, and the steroid was successfully stopped. After allogeneic transplantation, intestinal pneumatosis is a rather uncommon complications. Its pathogenesis is thought to be influenced by GVHD or steroids. Treatments for the disease may be incompatible with one another, and the response in individual cases needs to be studied in detail.

Clonal hematopoiesis of a novel dic(18;20) clone following allogeneic hematopoietic stem cell transplantation.

A 55-year-old man in first complete remission of acute myeloid leukemia with a normal karyotype underwent allogeneic hematopoietic stem cell transplantation from a human-leukocyte-antigen-matched sibling. Bone marrow examination on day 28 confirmed complete remission, but G-banding analysis revealed a novel chromosomal abnormality, including dic(18;20)(p11.2;q11.2). The patient developed moderate chronic graft-versus-host disease on day 174, and the abnormal clones identified by dic(18;20) significantly increased after that point. Chimerism testing repeatedly confirmed complete donor type. Although next-generation sequencing showed no clonal hematopoiesis-related gene mutations, copy number analysis of the donor and the recipient revealed copy number deletion of 18p, 18q, and 20q. The patient has maintained remission for more than 2 years to date without developing a hematologic neoplasm or cytopenia. The distinctive clonal hematopoiesis with a dicentric chromosome seemed to have undergone the breakage-fusion-bridge cycle, which could cause the complex events of deletion, amplification, and inversion. These copy number alterations might have increased the number of clones with growth advantage, and the highly inflammatory environment in the recipient due to graft-versus-host disease might have contributed to the clonal selection.