Here, we describe two patients with juvenile xanthogranuloma (JXG) manifesting with Langerhans cell histiocytosis-associated neurodegenerative disease (ND)-like radiological findings. One patient showed typical radiological abnormalities at onset, which worsened with progressing central nervous system symptoms 7 years after LCH-oriented chemotherapy. Another showed spontaneous regression of clinical symptoms, with a transient radiological change 1 year after salvage chemotherapy for recurrence of JXG. These data regarding JXG-associated ND will facilitate future investigation of the disease, as well as development of therapeutic interventions.

LETTER TO THE EDITOR

Detailed case reports of autologous recovery of hematopoiesis after hematopoietic stem cell transplantation with myeloablative conditioning (MAC) are scarce. We present a rare case of a 3-year-old male with relapsed KMT2A-rearranged acute lymphoblastic leukemia (ALL) who experienced autologous recovery following secondary engraftment failure after cord blood transplantation (CBT) with MAC. Similar to previous reports, we detected unusual chromosomal abnormalities, which differed at each bone marrow examination. He remains alive without relapse of ALL 12 months after CBT. As the rate of recurrence or late occurrence of secondary malignant neoplasm remains unclear, careful follow-up is required, especially in pediatric patients.

Acute undifferentiated leukemia (AUL) is a rare subtype of leukemia that expresses no lineage-specific markers; no optimal treatment for AUL has been established. Here, we report a 16-year-old female with CD22-positive refractory AUL who responded well to inotuzumab ozogamicin (InO). Minimal residual disease negativity was achieved using InO, followed by HLA-mismatched unrelated bone marrow transplantation (BMT). Although grade II veno-occlusive disease/sinusoidal obstruction syndrome occurred, it improved immediately. She remained disease-free at 10 months post-BMT, without severe complications (grade III–IV). This case demonstrates the feasibility of a treatment strategy using InO against CD22-positive AUL.