Unusual manifestations of acute leukemia. Case 1. CNS extramedullary relapse of acute promyelocytic leukemia after arsenic trioxide-induced remission

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.

Central nervous system relapse in a patient with acute promyelocytic leukaemia: does the risk stratification matter?

Extramedullary relapse is an uncommon complication of acute promyelocytic leukaemia (APL). The most common site of extramedullary relapse is the central nervous system (CNS), and the majority of CNS relapses occur in patients with high-risk disease in which white blood cell count at presentation is greater than 10×10(3)/μL. The best management of such patients is still controversial. We describe a 47-year-old man with APL who developed two CNS relapses which were diagnosed through the presence of t(15;17)(q22;q21) on PCR of the cerebrospinal fluid (CSF), despite presenting initially with intermediate-risk disease. We conclude that the intermediate risk group is very heterogeneous and these patients sometimes may behave like high-risk patients. Also, clinicians should take into account symptoms that can be related to CNS relapse in patients with APL and consider lumbar puncture even if radiological imaging does not reveal anything.

Promyelocytic sarcoma of the spine: a case report and review of the literature

Myeloid sarcoma (MS, previously named granulocytic sarcoma or chloroma) is a rare extramedullary tumour of immature myeloid cells. It can be present before, concurrently with, or after the diagnosis of acute myeloid leukemia. MS is extremely uncommon in acute promyelocytic leukemia (APL). In the case described here, MS was the sole site of APL relapse and the cause of spinal cord compression. The patient presented with neurologic symptoms due to a paravertebral mass of MS after 7 years of complete remission. He was treated with excision of the mass followed by local radiotherapy. Systemic treatment was also given with combined arsenic trioxide and all-trans retinoic acid and the patient was able to achieve a second prolonged clinical and molecular remission.

Arsenic trioxide: safety issues and their management

Arsenic trioxide (As2O3) has been used medicinally for thousands of years. Its therapeutic use in leukaemia was described a century ago. Recent rekindling in the interest of As2O3 is due to its high efficacy in acute promyelocytic leukaemia (APL). As2O3 has also been tested clinically in other blood and solid cancers. Most studies have used intravenous As2O3, although an oral As2O3 is equally efficacious. Side effects of As2O3 are usually minor, including skin reactions, gastrointestinal upset, and hepatitis. These respond to symptomatic treatment or temporary drug cessation, and do not compromise subsequent treatment with As2O3. During induction therapy in APL, a leucocytosis may occasionally occur, which can be associated with fluid accumulation and pulmonary infiltration. The condition is similar to the APL differentiation syndrome during treatment with all-trans retinoic acid, and responds to cytoreductive treatment and corticosteroids. Intravenous As2O3 treatment leads to QT prolongation. In the presence of underlying cardiopulmonary diseases or electrolyte disturbances, particularly hypokalaemia and hypomagnesaemia, serious arrhythmias may develop, with torsades du pointes reported in 1% of cases. This may be related to a dose-dependent arsenic-mediated inhibition of potassium ion channels that compromises cardiac repolarization. Because of slow intestinal absorption, oral-As2O3 gives a lower plasma arsenic concentration, which is associated with lesser QT prolongation and hence a more favorable cardiac safety profile. As2O3 does not appear to enter the central nervous system. However, if the blood brain barrier is breached, elemental arsenic may enter the cerebrospinal fluid. As2O3 is predominantly excreted in the kidneys, and dose adjustment is required when renal function is impaired.

Extramedullary disease and targeted therapies for hematological malignancies—is the association real?

During the past years targeted therapies have gained a major role in the treatment of cancer patients, including those with hematological malignancies. Extramedullary involvement is a rare manifestation of acute and chronic leukemias and of multiple myeloma. Nevertheless, with the expanding use of targeted treatments there is an impression that the incidence of extramedullary relapses is increasing. We reviewed the reports on this phenomenon in patients treated with all-trans-retinoic acid and arsenic trioxide for acute promyelocytic leukemia, thalidomide and bortezomib for multiple myeloma and imatinib for chronic myeloid leukemia. The pathogenetic mechanisms suggested are: life prolongation by these treatments allowing for disease progression arising from dormant cells; poor penetration of the drugs to sanctuary sites like the central nervous system; the requirement of some of these drugs, especially thalidomide, for the marrow microenvironment to exert their action; and finally, a possible active role for some of the drugs, like all-trans-retinoic acid. Since the use of these targeted therapies is expanding we should be aware of this association.

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.

CNS relapses of acute promyelocytic leukemia after all-trans retinoic acid

OBJECTIVE

To review the role of all-trans retinoic acid (ATRA) and arsenic trioxide in central nervous system (CNS) relapses of acute promyelocytic leukemia (APL).

CASE SUMMARY

A 69-year-old white man diagnosed with APL presented with bleeding diathesis. His molecular and cytogenetic studies were positive for promyelocytic leukemia-retinoic acid receptoralpha (PML-RARalpha) and t(15;17) transformation. Complete molecular and cytogenetic remission was achieved with ATRA, daunorubicin, and cytarabine. Within 6 months, the patient was readmitted for investigation of severe global headaches and an ataxic gait. His peripheral blood and cerebral spinal fluid were positive for PML-RARalpha fusion protein. Intrathecal chemotherapy and radiation, as well as ATRA, were the main treatment modalities provided. Molecular and cytogenetic remission was again obtained. Three months later, a second relapse occurred in the CNS and the peripheral blood.

DISCUSSION

APL is typically treated with anthacycline-based chemotherapy and ATRA. Approximately 85-95% of patients achieve complete remission (CR); however, the relapse rate has been reported to be about 30-40%. A thorough literature search (MEDLINE, EMBASE, CANCERLIT, 1966-January 2002) revealed only 54 cases of extramedullary disease, of which 35 involved the CNS.

CONCLUSIONS

The introduction of ATRA has improved patient survival dramatically. APL relapse, in general, has been in part attributable to repetitive or prolonged exposure to ATRA and the possibility of additional chromosomal changes, making the disease more refractory to treat. Given the evidence, one could argue that, with repeated ATRA treatment, CR duration may be shortened. However, limited data are available to guide the appropriate management of APL relapsed to the CNS with either ATRA, chemotherapy, or arsenic trioxide. In our opinion, treatment using arsenic trioxide is an unconventional option worthy of exploring.

Activity of all-trans-retinoic acid in a case of central nervous system extramedullary relapse of acute promyelocytic leukemia

We describe a patient with an acute promyelocytic leukemia (APL) previously treated with two courses of cytarabin, idarubicin and all-trans retinoic acid (ATRA), who presented a medullary and meningeal relapse after 8 months of complete remission. A diagnosis of central nervous system (CNS) involvement was based on the appearance of APL blasts in the cerebrospinal fluid (CSF); magnetic resonance (MR) imaging was negative. The neurological symptoms were not evident at the time of recognition of the medullary recurrence, but appeared a few days later, when the patient had already received a reinduction treatment. When the CSF was first examined, showing atypical promyelocytes, there was no excess of blasts on bone-marrow examination. The patient was treated with ATRA and intrathecal administrations of cytoxic drugs, achieving a complete long-lasting CNS remission. The appearance of mature myeloid cells in the CSF during this treatment suggested a possible differentiating effect of ATRA towards extramedullary relapse.

Combined arsenic trioxide and all-trans retinoic acid treatment for acute promyelocytic leukaemia recurring from previous relapses successfully treated using arsenic trioxide

The optimal treatment of acute promyelocytic leukaemia (APL) recurring from relapses successfully treated using arsenic trioxide (As2O3) is undefined. Three APL patients relapsing from As2O3-induced remission were studied. Re-treatment with As2O3 failed in one patient in third relapse, and resulted in morphological but not molecular remission in another patient. Combination therapy with As2O3 and all-trans retinoic acid (ATRA), however, resulted in morphological and molecular remission in all three cases, with a follow-up time ranging from 6 to 16 months. Our results suggest a synergistic therapeutic effect between As2O3 and ATRA in APL in advanced relapse.