[ENT manifestations of myeloid sarcoma]. / Manifestations ORL du ­sarcome ­myéloïde.

Myeloid sarcoma (MS) is a rare extra-medullary manifestation of acute myeloid leukaemia (AML) in the form of a first manifestation, progression or recurrence. Mostly located in the bones, it has the particularity of reaching the ENT sphere by mimicking common patho-logies, leading to a delay in diagnosis and treatment. The -mastoid involvement that we have encountered in our clinical -practice (clinical vignette) shows the complexity of identifying this pathology, with very few cases reported in the literature. The anamnesis, including a -history of AML, and the clinical examination help to guide the investigations. Targeted imaging, in this case CT/MRI combined with a biopsy of the lesion and a marrow puncture, is used to make the -diagnosis. Treatment with chemotherapy is indicated and rapidly initiated.

Le sarcome myéloïde (SM) constitue une rare manifestation extra­­médullaire de leucémie myéloïde aiguë (LMA) sous forme de première manifestation, progression ou récidive. Dans la majorité des cas de localisation osseuse, il présente la particularité ­d'atteindre la sphère ORL en mimant des pathologies communes entraînant un retard diagnostique et thérapeutique. L'atteinte mastoïdienne que nous avons rencontrée lors de notre pratique clinique (vignette clinique) montre la complexité d'identifier cette pathologie avec très peu de cas rapportés dans la littérature. L'anamnèse, avec notamment des antécédents de LMA, et l'examen clinique permettent d'orienter les investigations. Une imagerie ­ciblée, en l'occurrence scanner/IRM, associée à une biopsie de la lésion ainsi qu'une ponction de moelle permettent de poser le diagnostic. Le traitement par chimiothérapie est indiqué et rapide­ment débuté par la suite.

Association of immune evasion in myeloid sarcomas with disease manifestation and patients' survival.

Introduction: Myeloid sarcomas (MS) comprise rare extramedullary manifestations of myeloid neoplasms with poor patients' outcome. While the clinical relevance of the tumor microenvironment (TME) is well established in many malignancies, there exists limited information in MS. Methods: The expression of the human leukocyte antigen class I (HLA-I) antigens, HLA-I antigen processing and presenting machinery (APM) components and the composition of the TME of 45 MS and paired bone marrow (BM) samples from two independent cohorts were assessed by immunohistochemistry, multispectral imaging, and RNA sequencing (RNAseq). Results: A significant downregulation of the HLA-I heavy chain (HC; 67.5%) and ß2-microglobulin (ß2M; 64.8%), but an upregulation of HLA-G was found in MS compared to BM samples, which was confirmed in a publicly available dataset. Moreover, MS tumors showed a predominantly immune cell excluded TME with decreased numbers of tissue infiltrating lymphocytes (TILs) (9.5%) compared to paired BM (22.9%). RNAseq analysis of a subset of 10 MS patients with preserved and reduced HLA-I HC expression revealed 150 differentially expressed genes and a significantly reduced expression of inflammatory response genes was found in samples with preserved HLA-I expression. Furthermore, low HLA-I expression and low TIL numbers in the TME of MS cases were linked to an inferior patients' outcome. Discussion: This study demonstrated a high prevalence of immune escape strategies in the pathogenesis and extramedullary spread of MS, which was also found in patients without evidence of any BM pathology, which yields the rational for the development of novel individually tailored therapies for MS patients.

Myeloid sarcoma in JAK2-positive myelodysplastic neoplasms with fibrosis: a case report and literature review.

Myeloid sarcoma (MS) occurs in patients with acute myeloid leukemia (AML). In rare cases, MS can represent a form of blast transformation in patients with myeloproliferative neoplasms (MPN), myelodysplastic neoplasms (MDS), or MDS/MPN. The most frequent chromosomal alterations in MS are t(8;21) or inv(16), with other alterations being reported. Cases of MS in Janus kinase 2 (JAK2)-positive MDS with fibrosis are exceedingly rare. Here, we describe such a case. To the best of our knowledge, this is the first report of a JAK2 V617F mutation-positive MDS case occurring concurrently with MS involving the posterior aspect of the left seventh rib. No clear association has been previously demonstrated between the intramedullary AML cytogenetics and extramedullary disease occurrence. Interestingly, samples from the intramedullary MDS and extramedullary mass in this patient presented the same JAK2 V617F mutation. Following a treatment regimen of azacitidine and venetoclax, the patient achieved complete remission. The chest CT scan showed that the seventh posterior rib mass disappeared. This case provides valuable information for the potential future treatment of this disease.

Myeloid sarcoma with plasmacytoid dendritic cell-like proliferation associated with IKZF1, ETV6 and DNMT3A mutations.

The classification of clonal plasmacytoid dendritic cell (pDC) proliferation associated with myeloid neoplasms remains a topic of ongoing debate. Although the fifth edition of the World Health Organization classification classifies clonal pDC proliferation into two categories, it is unclear whether this classification adequately captures the complexities of clonal pDC pathogenesis. We present a clinical case featuring myeloid sarcoma with pDC-like cells in cervical lymph nodes and bone marrow (BM). Analysis of biopsy specimens and BM aspirate revealed two distinct cellular populations expressing myeloid and pDC markers. One population exhibited myeloid leukemia and monocyte markers, including MPO, CD13, CD33, CD11b, and CD14, while the other manifested an immunophenotype reminiscent of pDCs, characterized by expression of CD56 and CD123. Additionally, whole exome sequencing and RNA sequencing of BM mononuclear cells were conducted to explore the pathophysiology of this rare malignancy, and unveiled pDC-like cell proliferation driven by IKZF1 and ETV6 mutations originating from clonal hematopoiesis initiated by a DNMT3A mutation. Notably, venetoclax-based therapy exhibited efficacy for achieving and sustaining complete remission. This case provides pivotal insights into the mechanistic aspects of pDC/pDC-like cell proliferation in myeloid sarcoma, offering valuable perspectives on therapeutic strategies.

Acute Myeloid Leukemia with Myelodysplasia - Related Changes after Isolated Myeloid Sarcoma.

BACKGROUND: As a tumor mass, a myeloid sarcoma consists of myeloid blasts and presents at an anatomical site other than the bone marrow. In about one quarter of cases, myeloid sarcoma happens without an underlying acute myeloid leukemia or other myeloid neoplasm, and it may precede or coincide with AML or form acute blastic transformation of MDSs, MPNs, or MDS/MPNs. METHODS: Herein, we described a rare case of acute myeloid leukemia with myelodysplasia-related changes (AML-MRC), with WT1 mutation and high expression of TP53 after isolated myeloid sarcoma of lymph nodes showing a higher proportion of blasts, dysplasia of both megakaryocytes and granulocytes. CONCLUSIONS: The case highlights the importance of a bone marrow examination, including morphology, immunophenotyping, cytogenetic, and molecular examination in all cases to exclude the possibility of myeloid sarcoma, especially the morphological feature of bone marrow dysplasia in the early stage before AML.

Solitary eosinophilic granulocytic sarcoma in a dog.

A 6-year-old male golden retriever presented with swelling of the left upper eyelid of 2 months duration, which did not improve following a course of antibiotics. Routine serum biochemistry, complete blood count and diagnostic imaging identified no clinically significant abnormalities. The mass was surgically excised, and histopathologic examination was performed. Eosinophilic granulocytic sarcoma (GS) was diagnosed based on the results of histopathology and immunohistochemistry. This is the first report of GS affecting the eyelid of a dog.

Rapid progression from MDS to AML with gastric submucosal tumour as an extramedullary infiltration.

We present a rare case of myeloid sarcoma in the stomach of an elderly woman initially diagnosed with anaemia. Myeloid sarcoma, an unusual extramedullary manifestation of acute myeloid leukaemia (AML), primarily affects lymph nodes, bones, spine and skin, with gastrointestinal involvement being infrequent. Despite normal results from the initial endoscopy, a follow-up examination after 4 months revealed multiple submucosal gastric tumours. These developments coincided with worsening of anaemia and an increase in peripheral myeloblasts. Pathological evaluation and immunohistochemical staining confirmed gastric extramedullary infiltration associated with AML. This case highlights the importance of comprehensive diagnostic processes when suspecting leukaemic transformations, especially in myelodysplastic syndrome (MDS). Due to financial constraints, additional critical studies such as cytogenetics and next-generation sequencing were not performed. Nonetheless, this rare case demonstrates the visual observation of rapid progression from MDS to AML and concurrent early myeloid sarcoma development in an elderly patient.

An isolated sacral promyelocytic sarcoma in a child: A rare case report with emphasis on cytomorphology.

Myeloid sarcoma (MS) is an uncommon localized extramedullary tumor composed of immature myeloid precursor cells that can affect any organ. Promyelocytic sarcoma (PS), an extremely rare subtype of MS, is characterized by immature myeloid cells with features of acute promyelocytic leukemia (APL). We describe a case of pediatric PS that presented as a solitary sacral mass without any evidence of systemic or bone marrow involvement. The cytopathologic evaluation using touch imprint demonstrated numerous blasts with bilobed nuclei, cytoplasmic hyper-granularity, and aggregates of Auer rods, which are typical cytomorphologic features of APL. Herein, we report an extremely rare case of isolated PS in a child, emphasizing the importance of cytomorphologic evaluation, which is complemented by the findings from a comprehensive work-up.

The immutable relevance of myeloid sarcomas: Clinicopathological study of fourteen cases.

An extramedullary myeloid tumor or chloroma is an infrequent manifestation of a myeloid neoplasm. It is considered an equivalent to an acute myeloid leukemia. It is confirmed through biopsy, where infiltrating neoplastic myeloid cells distort the parenchyma. A total of twenty-nine cases were diagnosed as MS between 198 and 2023. Upon re-evaluation, only fourteen cases fulfilled the criteria for MS. The most common differential diagnosis were lymphomas, leukemic infiltration, and extramedullary hematopoiesis. Few were isolated cases; the rest were in the context of progression of a myeloid neoplasm. The majority had a myelomonocytic morphology and immunophenotype. The most reliable markers were CD45, HLA-DR, CD68 and CD4. The study highlights the complexity and impact of an accurate diagnosis of a myeloid sarcoma.

Brain-Decellularized ECM-Based 3D Myeloid Sarcoma Platform: Mimicking Adaptive Phenotypic Alterations in the Brain.

Leukemia circulates in the bloodstream and induces various symptoms and complications. Occasionally, these cells accumulate in non-marrow tissues, forming a tumor-like myeloid sarcoma (MS). When the blast-stage leukemia cells invade the brain parenchyma, intracranial MS occurs, leading to a challenging prognosis owing to the limited penetration of cytostatic drugs into the brain and the development of drug resistance. The scarcity of tissue samples from MS makes understanding the phenotypic changes occurring in leukemia cells within the brain environment challenging, thereby hindering development of effective treatment strategies for intracranial MS. This study presents a novel 3D in vitro model mimicking intracranial MS, employing a hydrogel scaffold derived from the brain-decellularized extracellular matrix in which suspended leukemia cells are embedded, simulating the formation of tumor masses in the brain parenchyma. This model reveals marked phenotypic changes in leukemia cells, including altered survival, proliferation, differentiation, and cell cycle regulation. Notably, proportion of dormant leukemia stem cells increases and expression of multidrug resistance genes is upregulated, leading to imatinib resistance, mirroring the pathological features of in vivo MS tissue. Furthermore, suppression of ferroptosis is identified as an important characteristic of intracranial MS, providing valuable insights for the development of targeted therapeutic strategies.

[Clinical Significance of Genetic and Molecular Changes in Primary Myeloid Sarcoma].

OBJECTIVE: To investigate the clinical significance of genetic and molecular changes in primary myeloid sarcoma (MS). METHODS: Fourteen patients with primary MS were selected in Jiading District Central Hospital Affiliated Shanghai University of Medicine & Health Sciences, The First People's Hospital of Lianyungang from September 2010 to December 2021. AML1-ETO fusion, PML-RARα fusion and CBFß breakage were detected by fluorescence in situ hybridization (FISH), and the mutations of NPM1, CEBPA, FLT3, RUNX1, ASXL1, KIT and TP53 genes were detected by new generation sequencing (NGS). RESULTS: Among 14 patients, the MS occurred in bone, breast, epididymis, lung, chest wall, cervix, small intestine, ovary, lymph nodes and central nervous system. The tumor cells expressed MPO (13 cases), CD34 (7 cases), CD43 (8 cases), CD68 (7 cases), CD99 (8 cases) and CD117 (6 cases). Cytogenetic abnormalities were observed in 4 cases, including 3 cases of AML1-ETO fusion and 1 case of CBFß breakage, while no PML-RARα fusion was detected. There were no significant differences in overall survival (OS) and leukemia-free survival (LFS) between patients with and without AML1-ETO fusion/CBFß breakage (both P >0.05). Among the 14 patients, the number of NPM1, CEBPA, FLT3-ITD, RUNX1, ASXL1, KIT and TP53 gene mutations was 5, 3, 5, 3, 2, 2, 1, respectively, of which 7 cases had at least one mutation in FLT3-ITD, RUNX1, ASXL1 and TP53 gene. The OS and LFS of patients with FLT3-ITD, RUNX1, ASXL1 or TP53 mutation were shorter than those without mutations (both P <0.01). CONCLUSION: The genetic and molecular abnormalities of primary MS can be detected by FISH and NGS techniques. FLT3-ITD, RUNX1, ASXL1 or TP53 mutation indicates a worse prognosis, but further clinical studies are needed to confirm it.

Spinal Myeloid Sarcoma in a Non-Leukaemic Patient.

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CNS erythroblastic sarcoma: a potential emerging pediatric tumor type characterized by NFIA::RUNX1T1/3 fusions.

Erythroblastic sarcoma (ES) (previously called chloroma or granulocytic sarcoma) are rare hematological neoplams characterized by the proliferation of myeloid blasts at extramedullary sites, and primarily involve the skin and soft tissue of middle-aged adults. ES may be concomitant with or secondary to myeloid neoplasms (mostly acute myeloid leukemia (AML)) or in isolated cases (de novo) without infiltration of the bone marrow by blasts. ES share cytogenetic and molecular abnormalities with AML, including RUNX1T1 fusions. Some of these alterations seem to be correlated with particular sites of involvement. Herein, we report an isolated erythroblastic sarcoma with NFIA::RUNX1T1 located in the central nervous system (CNS) of a 3-year-old boy. Recently, two pediatric cases of CNS MS with complete molecular characterization have been documented. Like the current case, they concerned infants (2 and 3 years-old) presenting a brain tumor (pineal involvement) with leptomeningeal dissemination. Both cases also harbored a NFIA::RUNX1T3 fusion. ES constitutes a diagnostic challenge for neuropathologists because it does not express differentiation markers such as CD45, and may express CD99 which could be confused with CNS Ewing sarcoma. CD43 is the earliest pan-hematopoietic marker and CD45 is not expressed by erythroid lineage cells. E-cadherin (also a marker of erythroid precursors) and CD117 (expressed on the surface of erythroid lineage cells) constitute other immunhistochemical hallmarks of ES. The prognosis of patients with ES is similar to that of other patients with AML but de novo forms seem to have a poorer prognosis, like the current case. To conclude, pediatric ES with NFIA::RUNX1T1/3 fusions seem to have a tropism for the CNS and thus constitute a potential pitfall for neuropathologists. Due to the absence of circulating blasts and a DNA-methylation signature, the diagnosis must currently be made by highlighting the translocation and expression of erythroid markers.

Myeloblastic meningeal neoplasm: an unusual natural history.

Myeloid sarcoma is a very rare extramedullary malignant tumour, most often associated with acute myeloid leukaemia. We report the case of a man in his early 20s who presented with chronic headache, raised intracranial pressure and progressive vision loss of 2 years duration with no systemic manifestations. He had a history of myeloid sarcoma of the left thigh 15 years ago, treated with external beam radiotherapy and in complete remission for more than 13 years. However, the progressive blindness remained unexplained for 2 years, and he was eventually diagnosed with isolated meningeal relapse without marrow or systemic involvement. Imaging revealed subarachnoid haemorrhage, diffuse leptomeningeal enhancement and involvement of lower dorsal cord and conus, and cerebrospinal fluid cytology showed myeloid blasts. He was managed with intrathecal chemotherapy and craniospinal irradiation, after which he had mild improvement in vision.

18 F-FDG PET/CT Imaging of Isolated Myeloid Sarcoma in the Right Humerus.

ABSTRACT: Myeloid sarcoma is a neoplastic mass formed by the infiltration of primitive or immature myeloid cells into organs and tissues outside the bone marrow. It may occur before, at the same time, or manifest as the recurrence of acute myeloid leukemia, myelodysplastic syndromes, and chronic myeloproliferative syndromes. It may involve any organ or tissue, including skin, soft tissue, lymph nodes, and gastrointestinal tract and bone. Isolated humerus involvement is extremely rare. Herein, we present the FDG PET/CT findings of a rare case of isolate myeloid sarcoma in the right humerus, which showed only increased bone density with moderate FDG uptake.