A rare case of acute basophilic leukemia transformed from high risk myelodysplastic syndrome

Acute basophilic leukemia (ABL) transformed from myelodysplastic syndrome is exceedingly rare. We report the case of a 73-year-old man with ABL which transformed from IPSS-M High risk MDS. The patient had a history of metastatic castration-sensitive prostate cancer. Further investigations demonstrated circulating blasts on peripheral blood smear. Upon bone marrow examination, a diagnosis of ABL arising from underlying MDS was established, characterized by cytogenetic analysis demonstrating trisomy 8 (+ 8), with the additional copy of chromosome 8 present in the form of a ring chromosome, and a WT1 frameshift mutation. The patient was treated with azacitidine and venetoclax, followed by best supportive care after disease progression. This case highlights the rare occurrence of ABL secondary to MDS and provides insight into the diagnostic challenges, clonal evolution, and therapeutic limitations associated with this aggressive entity.