title: Microgranular acute promyelocytic leukemia presenting with leukopenia and an unusual immunophenotype.
abstract: The microgranular variant (M3v) of acute promyelocytic leukemia (APL) is rare, and the diagnosis can be delayed due to variability in how this condition presents. M3v blasts often have folded nuclei, but unlike traditional APL blasts, they often possess faint granules without Auer rods. In addition, microgranular APL often presents with an elevated or normal white blood cell count in contrast with the leukopenia seen in traditional APL. In APL, delayed diagnosis can lead to early death from disseminated intravascular coagulation (DIC), which is the main cause of mortality in an otherwise treatable, and often curable, leukemia. We describe a 19-year-old male with microgranular APL who presented with leukopenia and many blasts resembling non-APL AML blasts with an unexpected immunophenotypic pattern. He was treated for DIC and initiated on all-trans-retinoic acid and arsenic trioxide; he achieved complete molecular remission after induction therapy. Suspicion for APL should always remain high in the presence of clinical manifestations of the disease in order that appropriate treatment can be initiated rapidly to prevent early death.
authors.affiliation: Carolinas Medical Center, Charlotte, NC, USA.
authors.forename: Megan H
authors.initials: MH
authors.lastname: McDonnell
authors.affiliation: Carolinas Pathology Group, PA, Carolinas Medical Center-Mercy, Charlotte, NC, USA.
authors.forename: Elton T
authors.initials: ET
authors.lastname: Smith
authors.affiliation: Carolinas Pathology Group, PA, Charlotte, NC, USA.
authors.forename: Edward H
authors.initials: EH
authors.lastname: Lipford
authors.affiliation: Levine Cancer Institute, Carolinas HealthCare System, Charlotte, NC, USA.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Gerber
authors.affiliation: Levine Cancer Institute, Carolinas HealthCare System, Charlotte, NC, USA. Electronic address: michael.grunwald@carolinashealthcare.org.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Grunwald
mesh_terms: D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000627:therapeutic use; D001853:Bone Marrow / Q000473:pathology; D004211:Disseminated Intravascular Coagulation / Q000150:complications / Q000188:drug therapy; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D015473:Leukemia, Promyelocytic, Acute / Q000150:complications* / Q000175:diagnosis*; D007970:Leukopenia / Q000209:etiology*; D008297:Male; D010087:Oxides / Q000627:therapeutic use; D016896:Treatment Outcome; D014212:Tretinoin / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D001152:Arsenicals; D010087:Oxides; D014212:Tretinoin; D000077237:Arsenic Trioxide
keywords: APL; Acute promyelocytic leukemia; Early death; Hypogranular APL; Leukopenia; M3v; Microgranular APL