We herein report a rare case of BCR-ABL1-positive B-lymphoblastic lymphoma (B-LBL). An 18-year-old woman had a history of persistent left-sided chest pain. Positron emission tomography showed increased metabolic activity in the fifth rib, duodenum, and pancreas. The pathological findings of the pancreas, duodenum, and bone marrow confirmed the diagnosis of B-LBL. Polymerase chain reaction of duodenum and bone marrow also revealed a minor BCR-ABL1 fusion gene. She was diagnosed with BCR-ABL1-positive B-LBL and administered dasatinib and prednisolone. She achieved complete remission two weeks after the initiation of the treatment. She received stem cell transplantation after consolidation chemotherapy and sustained complete remission.

Patients with advanced-stage mycosis fungoides (MF) and Sézary syndrome (SS) have a poor prognosis. Allogeneic hematopoietic cell transplantation (HCT) is a potentially curative treatment option; however, since most patients with MF/SS are elderly, they often have difficulty in finding HLA-matched donors. In recent years, HCT from HLA-haploidentical donors (haplo-HCT) using posttransplant cyclophosphamide (PTCy) as graft-versus-host disease prophylaxis has been conducted for patients without HLA-matched donors. Infectious complications, particularly cutaneous bacterial infections, are common among patients with MF/SS. The lower incidence of severe infectious complications after haplo-HCT than after an unrelated cord blood transplantation could lead to lower transplant-related mortality. Here, we report on a patient with SS who was treated successfully with haplo-HCT with PTCy. The patient has remained in complete remission for more than 24 months.

Monoclonal gammopathy of undetermined significance (MGUS) is a benign but precancerous condition that can progress to multiple myeloma. Patients with MGUS are typically monitored closely for signs of disease progression, but in some cases, they may also develop renal insufficiency, a condition known as monoclonal gammopathy of renal significance (MGRS). In MGRS, M‐protein secreted by a nonmalignant or premalignant cell clone triggers renal damage by definition. Herein, we report a case of a 66‐year‐old Asian male with MGUS complicated by renal insufficiency. A kidney biopsy showed no evidence of renal injury mediated by M‐protein; instead, the direct infiltration of clonal cells into renal tissues was observed. Although five similar cases have been previously reported, our case is unique in that the involvement of clonal cells was directly confirmed by fluorescence in situ hybridization. Our findings suggest the need to consider a novel disease concept, as this phenomenon appears to be reproduced.