High-grade myelodysplastic syndrome in a pediatric multi-organ transplant recipient: A case report and literature review.

BACKGROUND: Pediatric myelodysplastic syndrome is a rare but life-threatening condition requiring prompt recognition and management. METHODS: We herein present the only reported case of a pediatric multi-organ transplant recipient developing myelodysplastic syndrome. RESULTS: The patient was a 14-year-old girl on chronic calcineurin inhibitor therapy who presented with peri-rectal pain approximately 13 years after liver, small bowel, and pancreas transplant. The initial workup revealed pancytopenia and parvovirus B19 viremia. Her definitive diagnosis was complicated by a lack of adequate bone marrow biopsy specimens and expert consultation that resulted in treatment for hemophagocytic lymphohistiocytosis. She was later diagnosed with high-grade myelodysplastic syndrome. Although curative treatment with chemotherapy and hematopoietic stem cell transplantation was strongly considered, it was not performed due to the child's rapid clinical progression, ventilator status, and active infections. The patient died approximately 6 months following symptom onset. CONCLUSIONS: This case emphasizes the importance of early recognition of myelodysplastic syndrome in multi-organ transplant recipients on chronic immunosuppression. Pancytopenia is a common presentation in the post-transplant period that requires thorough investigation. Multiple confounding considerations such as infection, immunosuppression, and systemic inflammation can delay the diagnosis of underlying hematological malignancies. Transplant care providers should be aware of myelodysplastic syndrome and advocate for a comprehensive evaluation, given early recognition and intervention can significantly improve outcomes.

The Missing LNK: Evolution from Cytosis to Chronic Myelomonocytic Leukemia in a Patient with Multiple Sclerosis and Germline SH2B3 Mutation.

Chronic myelomonocytic leukemia (CMML) is a rare but distinct hematological neoplasm with overlapping features of myelodysplastic syndrome (MDS) and myeloproliferative neoplasm (MPN). Individuals with CMML have persistent monocytosis and bone marrow dyspoiesis associated with various constitutional symptoms like fevers, unintentional weight loss, or night sweats. It is established that there is a strong association of CMML with preceding or coexisting autoimmune diseases and systemic inflammatory syndromes affecting around 20% of patients. Various molecular abnormalities like TET2, SRSF2, ASXL1, and RAS are reported in the pathogenesis of CMML, but no such mutations have been described to explain the strong association of autoimmune diseases and severe inflammatory phenotype seen in CMML. Germline mutation in SH2B adaptor protein 3 (SH2B3) had been reported before to affect a family with autoimmune disorders and acute lymphoblastic leukemia. In this report, we describe the first case of a female subject with many years of preceding history of multiple sclerosis before the diagnosis of CMML. We outline the evidence supporting the pathogenic role of SH2B3 p.E395K germline mutation, connecting the dots of association between autoimmune diseases and CMML genesis.