Acute promyelocytic leukemia with secondary myelofibrosis and positive CD34 expression.

Acute promyelocytic leukemia (APL) is characterized by a translocation t(15;17), which leads to the fusion of the promyelocytic leukemia (PML) gene with the retinoic acid receptor alpha (RARA) gene. This entity represents a true medical emergency due to the high risk of coagulopathy and disseminated intravascular coagulation (DIC); thus, early diagnosis is crucial to initiate treatment and achieve a better outcome. Here, we present a challenging case of APL in a 25-year-old male that mimicked classic acute myeloid leukemia (AML) based on morphologic and immunophenotypic features. Furthermore, marked myelofibrosis was identified in our patient - an unusual finding for APL. By sharing this observation, we emphasize the importance of a comprehensive approach in achieving an accurate and timely diagnosis of APL, including the integration of morphologic assessment, immunohistochemistry, flow cytometry, and molecular techniques.