Case report: Acute myeloid leukemia M5

Abstract

Acute myeloid leukemia (AML) is a group of rapidly progressing, phenotypically and genetically heterogeneous malignant hematologic disorders characterized by the unregulated clonal proliferation of immature cells that have lost the ability to differentiate normally. Acute myeloid leukemia (AML) M5 represents approximately 10–15% of all adult AML cases and is characterized by ≥80% differentiation into the monocytic lineage. It has specific molecular implications that determine its clinical behavior and prognosis. The specific reciprocal chromosomal translocation particularly associated with the M5 (monocytic) morphological subtype is t(9;11)(p22;q23) and the KMT2A gene. Case report: A 63-year-old male patient presented with dyspnea on moderate to mild exertion, difficulty standing and requiring a wheelchair for mobility, concomitant skin and mucous membrane pallor, arthralgia in the left elbow and right knee, and bicytopenia due to anemia and severe thrombocytopenia with leukocytosis. Conclusions: AML-M5 is characterized by the proliferation of immature monocytes. It is a highly aggressive myeloid neoplasm with a marked capacity for extramedullary infiltration. The diagnostic approach is based on the atypical presentation of the disease, initially manifesting as a polyarticular syndrome with myeloproliferative symptoms and sacroiliitis (possibly paraneoplastic), which masked the hematological progression.