Central nervous system haemorrhage causing early death in acute promyelocytic leukaemia

A Case of Subacute Brain Hemorrhage and Disseminated Intravascular Coagulation Secondary to Acute Promyelocytic Leukemia in a Pediatric Patient

Acute promyelocytic leukemia (APML), characterized by the reciprocal translocation between chromosomes 15 and 17 [t(15;17)], is a result of proliferation of myeloid cells maturation which is interrupted at the promyelocytic stage. The central, and the most important, distinguishing feature of APML is a predisposition to disseminated intravascular coagulation (DIC). The overall prognosis of APML is very good, with 90% of patients achieving complete remission. We find it important to remind pediatric practitioners, both in the ambulatory and urgent care room settings, of presenting signs and symptoms of leukemia, as well as, up-to-date on management of such fulminant scenarios as DIC. Intracranial hemorrhage (ICH) is one of the commonest, and frequently fulminant complication of APML seen after initiation of induction chemotherapy. We report on a young female presenting with non-specific upper respiratory illness symptoms and recurrent headache, who was found to already have ICH and to be in DIC in the setting of APML at the time of initial evaluation. This case illustrates importance of thorough assessment and prompt consideration of wide differential diagnosis, which became somewhat limited and biased towards web-based telemedicine in the COVID-19 pandemics era.

Pediatric Acute Promyelocytic Leukemia Presenting to the Emergency Department as Refusal to Ambulate

A previously healthy 10-year-old girl presented to the emergency department (ED) with a headache and vomiting which resolved with oral NSAIDs. The patient returned two days later unable to ambulate with mental slowing and lower extremity bruising. Labs demonstrated marked leukocytosis, severe anemia and thrombocytopenia, and disseminated intravascular coagulation (DIC). Brain MRI showed multiple intracranial hemorrhages. A peripheral blood smear demonstrated blasts with many Auer rods. A diagnosis of acute promyelocytic leukemia (APL) was made and therapy including all-transretinoic acid (ATRA) was initiated. Neurologic status returned to baseline within 1 week in the pediatric intensive care unit.

PML(NLS¯) protein: A novel marker for the early diagnosis of acute promyelocytic leukemia

Promyelocyte leukemia-retinoic acid receptor α (PML-RARα) is known as a fusion gene of acute promyelocytic leukemia (APL). Previous studies have reported that neutrophil elastase (NE) cleaves PML-RARα in early myeloid cells, which leads to the removal of the nuclear localization signal (NLS) in PML and increases the incidence of APL. The resultant PML without the NLS is termed PML(NLS⁻). The aim of the present study was to verify the existence and location of the PML(NLS⁻) protein in NB4 cells. NB4 cells underwent electroporation with the pCMV-HA-NE plasmid to form NB4-HA-NE cells, which were then transplanted to produce tumors in nude mice and samples were collected from patients with APL. Western blot analysis, an immunofluorescence assay, confocal laser microscopy and immunohistochemistry were performed to detect the expression and localization of the PML(NLS⁻) protein. The findings demonstrated that PML(NLS⁻) was detectable in the cytoplasm of NB4-HA-NE cells, the tumors in nude mice and in neutrophils from patients with APL. This indicated that PML(NLS⁻) may be an effective and novel target for the diagnosis of APL.