A Case of Mistaken Identity: When All Mimics AML.

A 39-year-old man was diagnosed with acute lymphoblastic leukaemia (B-ALL) with SYNRG::ZNF384 and P2RY8::CRLF2 gene fusions. He was treated according to the GRAALL 2014 and underwent an allogeneic transplantation, achieving complete remission. Twenty-five months later, he developed pancytopenia. The bone marrow examination showed blasts with an immunophenotype consistent with minimally differentiated acute myeloid leukaemia (AML M0). Although the P2RY8::CRLF2 fusion persisted, no molecular evidence of a lineage switch was detected. This rare presentation underlines the diagnostic challenges of acute leukaemias. The patient was finally treated with azacitidine and venetoclax.