Central nervous system relapse in acute promyelocytic leukemia

Leptomeningeal Relapse of Acute Promyelocytic Leukemia

Extramedullary relapse (EMR) of acute promyelocytic leukemia (APL) is a rare entity, with predilection to involve the central nervous system (CNS). Risk factors include leukocytosis of > 10 × 10⁹/L, bcr3 isoform, microgranular variant, age > 45 years and development of subarachnoid hemorrhage (SAH) during induction therapy. We report a case of APL who completed induction and consolidation therapy but subsequently relapsed with leptomeningeal involvement. Retrospectively, we identified several risk factors for EMR in our patient. Interestingly, the use of all-trans retinoic acid has recently been associated with higher risk of EMR possibly due to up-regulation of adhesion molecules on the surface of the leukemic cell, resulting in their passage through the endothelium to extramedullary tissues. However, data remain conflicting in that regard. Although universal CNS prophylaxis has been suggested, the low incidence of EMR among APL patients renders this strategy less attractive. Nonetheless, active surveillance and CNS prophylaxis may be considered in patients at high risk for EMR, particularly in those of SAH during induction therapy. Further research is needed to evaluate the effectiveness and safety of this strategy.

Prognostic significance of CD44v6/v7 in acute promyelocytic leukemia

CD44v, especially splice variants containing exon v6, has been shown to be related closely to development of different tumors. High levels of CD44v6/v7 have been reported to be associated with invasiveness and metastasis of many malignancies. The objective of this study was to detect expression of CD44v6-containing variants in patients with acute promyelocytic leukemia (APL) and evaluate the potential of CD44v6/v7 for risk stratification. Reverse transcription polymerase chain reaction (RT-PCR) followed by PCR product purification, ligation into T vectors and positive clone sequencing were used to detect CD44 v6-containing variant isoforms in 23 APL patients. Real-time quantitative PCR of the CD44v6/v7 gene was performed in patients with APL and in NB4 cells that were treated with all-trans retinoic acid (ATRA) or arsenic trioxide (As2O3). Sequencing results identified four isoforms (CD44v6/v7, CD44v6/v8/v10, CD44v6/v8/v9/v10, and CD44v6/v7/v8/v9/v10) in bone marrow mononuclear cells of 23 patients with APL. The level of CD44v6/v7 in high-risk cases was significantly higher than those with low-risk. Higher levels of CD44v6/v7 were found in three patients with central nervous system relapse than in other patients inthe same risk group. Furthermore, in contrast to ATRA, only As2O3 could significantly down-regulate CD44v6/v7 expression in NB4 cells. Our data suggest that CD44v6/v7 expression may be a prognostic indicator for APL.

Central nervous system relapse in CD56+, FLT3/ITD+ promyelocytic leukemia

Central nervous system (CNS) involvement in acute promyelocytic leukemia (APL) is rare and tends to be seen mostly following treatment with all-trans retinoic acid (ATRA), due to prolonged patient survival and poor penetration of the drug in the CNS. At least 10% of extramedullary relapses in APL involve the CNS, and associated factors include an increased age, the BCR isoform, the development of differentiation syndrome, a high white cell count at presentation and hemorrhage into the CNS during induction therapy. We present the case of a patient with high-risk APL, CD56+, CD2+ in whom a CNS relapse was diagnosed through the presence of a PML/RARα rearrangement on PCR of the cerebrospinal fluid (CSF).

Leptomeningeal neoplasia: epidemiology, clinical presentation, CSF analysis and diagnostic imaging

The incidence of leptomeningeal metastasis over the past several decades has increased among solid tumor patients and decerased in patients with hematologic malignancies. Improvements in systemic therapies are likely responsible for both changes; solid tumor patients are living longer and, threfore, are at higher risk to develop leptomeningeal tumors while patients with hematologic malignancy have benefitted from more aggressive central nervous system prophylaxis. Regardless, both types of patients present with symptoms referrable to multiple levels of the central nervous system and a careful dignostic approach incorporating cerebrospinal fluid studies and appropriate neuroimaging is critical.

Meningeal relapse in a patient with acute promyelocytic leukemia: a case report and review of the literature

The involvement of central nervous system is rare in acute promyelocytic leukemia (APL). We report a APL patient of a 41 yr-old Korean male who presented with fever and petechia. Complete molecular remission was achieved with all-trans retinoic acid (ATRA), idarubicin, and cytarabine. Ten months later, he complained of a mild headache. The results of the physical examination and the complete blood counts were normal. The examination of cerebrospinal fluid showed the presence of promyelocyte. Bone marrow studies showed cytogenetic remission but with molecular relapse. He was treated with intrathecal and systemic chemotherapy.