Atypical morphology and aberrant immunophenotypic expression: A diagnostic dilemma in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia, which is highly aggressive, yet the most curable. It is a medical emergency that requires a very high index of suspicion, as delay in the treatment could lead to fatality. The initial diagnosis is made on the basis of its typical clinical presentation, morphological and immunophenotypic features. However, definitive diagnosis rests on the cytogenetic study. We present one such interesting case of APL where the morphology as well as immunophenotypic features was quite deceiving, leading to a diagnostic dilemma.