Myeloid Sarcoma as a Manifestation of Lineage Switch from B-cell Acute Lymphoblastic Leukemia after Double Allogeneic Stem Cell Transplantation: A Case Report
Acta Haematologica Oncologica Turcica, cilt.59, sa.1, ss.63-65, 2026 (Scopus, TRDizin)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 59 Sayı: 1
- Basım Tarihi: 2026
- Doi Numarası: 10.4274/ahot.galenos.2026.2025-12-1
- Dergi Adı: Acta Haematologica Oncologica Turcica
- Derginin Tarandığı İndeksler: Scopus, TR DİZİN (ULAKBİM)
- Sayfa Sayıları: ss.63-65
- Anahtar Kelimeler: acute lymphoblastic leukemia, acute myeloid leukemia, allogeneic stem cell transplantation, extramedullary relapse, Lineage switch, myeloid sarcoma
- Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu
- Sağlık Bilimleri Üniversitesi Adresli: Evet
Özet
Phenotypic conversion between lymphoid and myeloid leukemic lineages is infrequent and generally associated with an unfavorable clinical prognosis. Most reported cases involve relapse of B-cell acute lymphoblastic leukemia (B-ALL) presenting as acute myeloid leukemia (AML). The development of extramedullary disease as myeloid sarcoma after lineage switch, particularly following sequential allogeneic hematopoietic stem cell transplantation (allo-HSCT), is exceedingly rare. A 36-year-old woman with Philadelphia chromosome-positive B-ALL achieved remission after chemotherapy and tyrosine kinase inhibitor-based therapy, but relapsed and underwent two consecutive allo-HSCTs from different donors. Eighteen months after the second transplantation, while in complete remission, she presented with localized knee pain. Imaging and histopathological evaluation confirmed myeloid sarcoma, and bone marrow analysis demonstrated AML, indicating a lineage switch. Treatment with local radiotherapy followed by venetoclax and azacitidine resulted in remission. This case highlights the importance of considering lineage switch in patients with atypical relapse patterns or isolated extramedullary lesions after allo-HSCT.