Extramedullary disease in acute promyelocytic leukemia: two-in-one disease

Treatment of a Patient with Acute Promyelocytic Leukemia with Multiple Isolated Relapses in the Central Nervous System: A Case Report and Mini-Review of the Literature

The efficacy of therapeutics for acute promyelocytic leukemia (APL) has exhibited an increase in recent years. Only a few patients experience relapse, including extramedullary relapse, and in patients with extramedullary relapse, the central nervous system (CNS) is the most common site. To date, there is no expert consensus or clinical guidelines available for CNS relapse, at least to the best of our knowledge. The optimal therapeutic strategy and management options for these patients remain unclear. The present study reports the treatment of a patient with APL with multiple isolated relapses in the CNS. In addition, through a mini-review of the literature, the present study provides a summary of various reports of this disease and discusses possible treatment options for these patients.

Treatment of Central Nervous System Relapse in Acute Promyelocytic Leukemia by Venetoclax: A Case Report

Extramedullary relapse of acute promyelocytic leukemia is a rare phenomenon and is associated with a poor prognosis, with the central nervous system being the most common site of relapse. The current treatments are still limited. Venetoclax, a selective inhibitor of BCL2, is a small molecule that can cross the blood-brain barrier and shows a potential efficacy in the treatment of chronic lymphocytic leukemia with central nervous system involvement. Although venetoclax has also been used in the treatment of acute myeloid leukemia in recent years, there are no reports of its use in the treatment of central nervous system relapse in acute promyelocytic leukemia. Here, we report a case of central nervous system relapse in acute promyelocytic leukemia that achieved complete remission after oral treatment with venetoclax. The presence of venetoclax in the patient’s CSF was confirmed by testing CSF and plasma by mass spectrometry. The concentration of venetoclax in CSF was approximately 1/300 of that in plasma trough concentration. The treatment experience in this case demonstrates the potential ability of venetoclax to treat of central nervous system relapse/involvement in acute promyelocytic leukemia, thus providing a new treatment option for this kind of patient.

Case Report: Very Late, Atypical Extra-Medullary Relapse in a Patient With Acute Promyelocytic Leukemia (APL) Rescued With a Transplant-Free Approach

Relapses of acute promyelocytic leukemia (APL) beyond 7 years from the first molecular remission are exceptional, and it is unclear whether these relapses represent a new, therapy-related leukemia rather than a delayed relapse of the original leukemic clone. The increase extra-medullary relapses (ER) in the era of all-trans retinoic acid (ATRA) therapy suggests a potential correlation between ATRA therapy and ER, and several potential explanations have been proposed. The gold standard post-remission approach, particularly for patients in late relapse, has not yet been established. The benefit of a transplant approach has been questioned in this setting because continuing ATRA-arsenic trioxide (ATO) might be curative. Here we report on the case of an APL patient who relapsed 9 years after achieving her first molecular complete remission (mCR) and who showed an atypical isolated localization at nodal sites, including the into- and peri-parotid glands. Genomic PML/RARa breakpoint analysis detected the same bcr3 PML/RARa hybrid gene in DNA purified from bone marrow and lymph nodes, suggesting that the relapse was because of the reemergence of the initial clone. This case shows that APL, treated with ATRA and cytotoxic drugs, may still emerge in extra-medullary sites even after a very prolonged mCR and could be salvaged with an ATO-based protocol, not including a transplant approach.

Central Nervous System Double Relapse of Acute Promyelocytic Leukemia and Acute Myelomonocytic Leukemia

Relapse of acute promyelocytic leukemia (APL) and non-M3-acute myeloid leukemia in the central nervous system (CNS) are rare events. Here, we describe a case of simultaneous relapses of APL and acute myelomonocytic leukemia on the CNS of a patient after allogeneic bone marrow transplant. This extremely unusual case highlights the difficulties that CNS leukemia relapses pose in the post-transplant setting.

Limited Tissue Samples: Hematopoietic Lesions - Three Case Examples of Judicious Use of Limited Material

In the era of smaller and smaller biopsies submitted to pathology departments for diagnosis and the advent of personalized medicine, it has become imperative to efficiently and effectively use patient material to reach individualized, actionable diagnoses. The use of fine needle aspirates and core biopsies as acceptable methods for obtaining sufficient material for hematopoietic neoplasms under nonemergent conditions is debatable. There are, however, scenarios where only limited material is obtainable due to anatomic site, size of the lesion or condition of the patient. In these types of settings, thoughtful approaches and unconventional means are often necessary to reach a diagnosis. In this article, we describe three such scenarios and the unique tactics taken in each to obtain a personalized actionable diagnosis.

Evolution of a FLT3-TKD mutated subclone at meningeal relapse in acute promyelocytic leukemia

Here, we report the case of an acute promyelocytic leukemia (APL) patient who—although negative for FLT3 mutations at diagnosis—developed isolated FLT3 tyrosine kinase II domain (FLT3-TKD)-positive meningeal relapse, which, in retrospect, could be traced back to a minute bone marrow subclone present at first diagnosis. Initially, the 48-yr-old female diagnosed with high-risk APL had achieved complete molecular remission after standard treatment with all-trans retinoic acid (ATRA) and chemotherapy according to the AIDA (ATRA plus idarubicin) protocol. Thirteen months after the start of ATRA maintenance, the patient suffered clinically overt meningeal relapse along with minute molecular traces of PML/RARA (promyelocytic leukemia/retinoic acid receptor alpha) in the bone marrow. Following treatment with arsenic trioxide and ATRA in combination with intrathecal cytarabine and methotrexate, the patient achieved a complete molecular remission in both cerebrospinal fluid (CSF) and bone marrow, which currently lasts for 2 yr after completion of therapy. Whole-exome sequencing and subsequent ultradeep targeted resequencing revealed a heterozygous FLT3-TKD mutation in CSF leukemic cells (p.D835Y, c.2503G>T, 1000/1961 reads [51%]), which was undetectable in the concurrent bone marrow sample. Interestingly, the FLT3-TKD mutated meningeal clone originated from a small bone marrow subclone present in a variant allele frequency of 0.4% (6/1553 reads) at initial diagnosis. This case highlights the concept of clonal evolution with a subclone harboring an additional mutation being selected as the “fittest” and leading to meningeal relapse. It also further supports earlier suggestions that FLT3 mutations may play a role for migration and clonal expansion in the CSF sanctuary site.

Extramedullary relapse in lumbar spine of patient with acute promyelocytic leukemia after remission for 16 years: a case report and literature review

Acute promyelocytic leukemia (APL) is a common myeloid leukemia. At the newly diagnosed stage, it can be fatal because of the serious complication-disseminated intravascular coagulation. With the advent and early application of all-trans retinoic acid, most APL patients can achieve a long-term survival, and only a minority of patients will develop extramedullary relapse after remission. The most common site of extramedullary relapse is central nervous system, while other sites are relatively rare. Here, we report a particularly rare APL patient who experienced extramedullary relapse with lumbar spine as the isolated site after a rather long time of remission for 16 years. At the time of relapse, the main clinical manifestations of the patient are obvious low back pain, weakness in lower limbs and limitation of activity. After treatment of local radiotherapy combined with ATRA and arsenic trioxide, the patient achieved and maintained a second complete remission by now.

Extramedullary relapse in RARA rearrangement-negative acute promyelocytic leukemia successfully treated in combination with chemotherapy, local radiotherapy, and cord blood transplantation

RARA rearrangement-negative acute promyelocytic leukemia (APL) is uncommon, and its extramedullary relapse is extremely rare. We report a 5-year-old girl with RARA rearrangement-negative APL, which recurred solely at the external auditory canal and mastoid air cells. She was successfully treated with chemotherapy, local radiotherapy, and unrelated cord blood transplantation. She has maintained complete remission for 24 months after transplantation. The clinical features and our therapeutic strategy in this patient will provide valuable information for extramedullary relapse of RARA rearrangement-negative APL.

Cerebrospinal fluid involvement in acute promyelocytic leukaemia at presentation

In acute promyelocytic leukaemia (APL), extramedullary disease (EMD) is rare but can occur in those who relapse following therapy. Although the most common site of EMD in APL is central nervous system (CNS) and skin, CNS involvement in recently diagnosed patients with APL is very rare and rarely described. We report cerebrospinal fluid involvement in a case of APL, on day 3 of induction therapy.

"Tear drops" in the cerebrospinal fluid: Correct by scatter, but pathognomonic by site

Extramedullary relapse in acute promyelocytic leukemia (APL) is rare, but occurs most commonly in central nervous system (CNS), generally in high-risk cases (total leucocyte count≥10,000/µL, atypical morphology or disseminated intravascular coagulation at presentation), and concomitant with bone marrow (BM) relapse. Here, we describe a case of APL who except for CD56 positivity was low risk but had a CNS relapse without concomitant BM involvement. Diagnosis of isolated CNS relapse was based on characteristic tear-drop pattern for CD45/side scatter plot on flow cytometry, a full compatible immunophenotype and cytomorphology in the cerebrospinal fluid. The case illustrates the value of the latter and the importance of including CD56 in risk assessment of APL.

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.