Differential clinical and prognostic impact of myeloid sarcoma vs medullary myeloid blast phase of chronic myelogenous leukemia in the era of tyrosine kinase inhibitor therapy

Chronic myeloid leukaemia with soft tissue mass formed by mature granulocytes

Extramedullary lesions in patients with chronic myeloid leukaemia (CML) suggest progression to the blast phase because such lesions generally consist of immature granulocytes. We here report a case of an extramedullary mass formed by mature granulocytes during the chronic phase of CML. A 60-year-old woman who had discontinued treatment for CML with dasatinib of her own accord several years ago presented to our hospital with a complaint of right thigh pain. She had a mass on her right leg, which was located on her right thigh and was elastic, soft and fist-sized. Blood tests and the bone marrow findings were compatible with the chronic phase of CML, and a CT-guided needle biopsy showed an infiltrate containing numerous mature neutrophils and foam cells. The mass disappeared with dasatinib alone, without antibacterial agents or drainage.Although the detailed pathogenesis of mass formation with mature granulocytes in the chronic phase of CML has not been elucidated, the clinical course of the current case highlights the importance of prompt biopsy, pathological examination and the early initiation of appropriate treatment.

Treatment of blast phase chronic myeloid leukaemia: A rare and challenging entity

Despite the success of BCR-ABL-specific tyrosine kinase inhibitors (TKIs) such as imatinib in chronic phase (CP) chronic myeloid leukaemia (CML), patients with blast phase (BP)-CML continue to have a dismal outcome with median survival of less than one year from diagnosis. Thus BP-CML remains a critical unmet clinical need in the management of CML. Our understanding of the biology of BP-CML continues to grow; genomic instability leads to acquisition of mutations which drive leukaemic progenitor cells to develop self-renewal properties, resulting in differentiation block and a poor-prognosis acute leukaemia which may be myeloid, lymphoid or bi-phenotypic. Similar advances in therapy are urgently needed to improve patient outcomes; however, this is challenging given the rarity and heterogeneity of BP-CML, leading to difficulty in designing and recruiting to prospective clinical trials. This review will explore the treatment of BP-CML, evaluating the data for TKI therapy alone, combinations with intensive chemotherapy, the role of allogeneic haemopoietic stem cell transplantation, the use of novel agents and clinical trials, as well as discussing the most appropriate methods for diagnosing BP and assessing response to therapy, and factors predicting outcome.

Incidence, clinical characteristics, and prognostic nomograms for patients with myeloid sarcoma: A SEER-based study

Background

Myeloid sarcoma (MS) is a rare hematological tumor that presents with extramedullary tumor masses comprising myeloid blasts. A controversial issue is whether MS involving normal hematopoietic sites (liver, spleen, and lymph nodes) should be excluded in future studies. We aimed to compare MS characteristics and outcomes involving hematopoietic and non-hematopoietic sites and construct a prognostic nomogram exclusively for the latter.

Methods

Data from patients diagnosed with MS between 2000 and 2018 were collected from the Surveillance, Epidemiology, and End Results (SEER) database. According to the primary site, patients were classified as having MS involving hematopoietic sites (hMS) or non-hematopoietic sites (eMS). Clinical characteristics and survival outcomes were compared between the two groups using Wilcoxon, chi-square, and log-rank tests. Cox regression analysis was used to identify eMS prognostic factors to establish prognostic nomograms. The models’ efficiency and value were assessed using receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA).

Results

In total, 694 patients were enrolled, including 86 with hMS and 608 with eMS. There were no sex, race or marital status distribution differences between the two groups. Patients with eMS had better overall and cancer-specific survival rates than those with hMS. Additionally, prognostic factor effects differed between the two groups. Patients with eMS were randomly divided into the training (number of patiens, n=425) and validation cohorts (n=183). Age, first primary tumor, primary site, and chemotherapy were used to establish nomograms. The C-index values of overall survival (OS) and cancer-specific survival (CSS) nomograms were 0.733 (validation: 0.728) and 0.722 (validation: 0.717), respectively. Moreover, ROC, calibration curves, and DCA confirmed our models’ good discrimination and calibration ability and potential clinical utility value.

Conclusion

Our study described the differences between patients with eMS and those with hMS. Moreover, we developed novel nomograms based on clinical and therapeutic factors to predict patients with eMS’ 1-, 3- and 5-year survival rates.

The Progression of Chronic Myeloid Leukemia to Myeloid Sarcoma: A Systematic Review

Chronic myeloid leukemia (CML) is a slow-growing type of cancer that originates in the blood-forming cells of the bone marrow and is caused by a chromosomal mutation that is thought to occur spontaneously. CML could potentially lead to the development of myeloid sarcoma (MS), which is a rare neoplasm composed of immature myeloid cells that could evolve into a tumor mass at any anatomical site other than the bone marrow. MS can develop spontaneously or as a result of another form of myeloid neoplasm. Most instances of CML precede blast phase (BP) within two to three years after the first diagnosis of CML chronic phase (CP) at the age of pre-tyrosine kinase inhibitor (TKI) treatment. MS developing in CML patients during the era of TKI treatment is infrequently mentioned in the literature, primarily in single-case studies. As a result, the prognostic influence of MS in CML patients has not been well investigated. In the age of TKI treatment, it is uncertain whether MS and medullary BP have comparable clinical and prognostic relevance. The precise diagnosis of MS is critical for effective treatment, which is frequently delayed due to a high risk of misdiagnosis. This review focuses on the relationship between the development of MS from CML, and it culminates with recommendations for future hematology practice. A literature search was conducted in multiple databases, and the studies were appraised based on the inclusion and exclusion criteria. Finally, studies to date have shown that the existence of CML and its possible progression to MS in individuals map out the numerous implications this disease has in hematology practice. Though occurrences are uncommon in general, the prognosis for patients is bleak, necessitating the exploration and implementation of diagnostic and therapy advancements. Because there is limited evidence in the literature on its existence in the medullary chronic phase and outcomes in the era of TKI, it must be carefully investigated because it might be the first symptom of progressive illness prior to hematological progression.

Myeloid sarcoma: an uncommon presentation of myeloid neoplasms; a case series of 4 rare cases reported in a tertiary care institute

Myeloid sarcoma (MS) is a rare extramedullary neoplasm of myeloid cells, which can arise before, concurrently with, or following hematolymphoid malignancies. We report 04 such cases of MS, diagnosed in this institute over a period of 6 years, during various phases of their respective myeloid neoplasms/leukemias. These cases include MS occurring as a relapse of AML (Case 1), MS occurring as an initial presentation of CML (Case 2), MS occurring during ongoing chemotherapy in APML (Case 3), and MS presenting as a progression of MDS to AML (Case 4). In the absence of relevant clinical history and unemployment of appropriate immunohistochemical (IHC) studies, these cases have a high risk of being frequently misdiagnosed either as Non-Hodgkin’s Lymphoma (NHL) or small round cell tumors or undifferentiated carcinomas, which may further delay their management, making an already bad prognosis worse. This case series has been designed to throw light on the varied presentation of MS and the lineage differentiation of its neoplastic cells through the application of relevant IHC markers along with their clinical correlation.

Clonal evolution of AML1-ETO coexisting with BCR-ABL and additional chromosome abnormalities in a blastic transformation of chronic myeloid leukemia

Blast crisis develops in a minority of patients with chronic myeloid leukemia even in the era of tyrosine kinase inhibitor (TKI) therapy. Reports suggest that we know little about the mechanism of BCR-ABL and AML1-ETO co-expression in blast crisis of chronic myeloid leukemia, and that other chromosomal abnormalities also coexist. Here, we document an unusual and interesting case of a 51-year-old female diagnosed in the chronic phase of chronic myeloid leukemia. After undergoing TKI treatment for 3 months, her bone marrow aspirates in the chronic phase had transformed to blast crisis. Molecular genetic testing indicated she was positive for p210 form of BCR-ABL (copy number decreased from 108.91% to 56.96%) and AML1-ETO fusion (copy number, 5.65%) genes and had additional chromosomal abnormalities of t(8; 21)(q22; q22)/t(9; 22)(q34; q11), t(2; 5)(p24; q13) and an additional +8 chromosome.

Cytogenetics-based risk prediction of blastic transformation of chronic myeloid leukemia in the era of TKI therapy

The high fatality of patients with blast phase (BP) chronic myeloid leukemia (CML) necessitates identification of high-risk (HR) patients to prevent onset of BP. Here, we investigated the risk of BP based on additional chromosomal abnormality (ACA) profiles in a cohort of 2326 CML patients treated with tyrosine kinase inhibitors (TKIs). We examined the time intervals from initial diagnosis to ACA emergence (interval 1), from ACA emergence to onset of BP (interval 2), and survival after onset of BP (interval 3). Based on BP risk associated with each ACA, patients were stratified into intermediate-1, intermediate-2, and HR groups, with a median duration of interval 2 of unreached, 19.2 months, and 1.9 months, respectively. There was no difference in durations of intervals 1 or 3 among 3 groups. Including patients without ACAs who formed the standard-risk group, the overall 5-year cumulative probability of BP was 9.8%, 28.0%, 41.7%, and 67.4% for these 4 groups, respectively. The pre-BP disease course in those who developed BP was similar regardless of cytogenetic alterations, and 84.4% of BP patients developed BP within the first 5 years of diagnosis. In summary, interval 2 is the predominant determinant of BP risk and patient outcome. By prolonging the duration of interval 2, TKI therapy mitigates BP risk associated with low-risk ACAs or no ACAs but does not alter the natural course of CML with HR ACAs. Thus, we have identified a group of patients who have HR of BP and may benefit from timely alternative treatment to prevent onset of BP.