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.

Myeloid sarcoma (MS) is a rare extramedullary parenchymal tumor composed of immature myeloid cells, occurring mainly in the lymph nodes, skin, soft tissue, testicles, bones, peritoneum, and gastrointestinal tract, and rarely in the pancreas. Herein, we report the case of a 68-year-old female patient who visited our hospital for medical assistance due to acute abdominal pain. Abdominal computed tomography (CT) and magnetic resonance imaging showed a mass approximately 8 cm in diameter in the pancreatic tail, which was suspected to be a malignant tumor. To further assess the presence of distant metastases, the patient underwent fluorine-18-fluorodeoxyglucose positron emission tomography (18F-FDG PET)/CT, which revealed an increased 18F-FDG uptake in the corresponding lesions. Subsequently, the patient underwent surgical treatment, and postoperative pathology and immunohistochemistry revealed that the mass was MS. Moreover, we reviewed the clinical features, imaging findings, and histopathology of pathologically confirmed pancreatic MS in the published literature.

UNASSIGNED: 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.
UNASSIGNED: 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).
UNASSIGNED: 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.
UNASSIGNED: 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.

OBJECTIVE: Myeloid sarcoma (MS) is a rare tumour comprising myeloid blasts occurring at an anatomical site other than the bone marrow. We sought to investigate both paediatric and adult patients with MS diagnosed at our institution and determine possible correlations among their clinicopathological, phenotypic, molecular and prognostic features.
METHODS: This study retrospectively evaluated the data of 45 patients diagnosed with MS at Ege University Faculty of Medicine Hospital, Turkey, over a 17-year period.
RESULTS: The male-to-female ratio was 1.5:1, and the median age was 39.12 years. The most commonly involved sites were the skin, lymph nodes, soft tissues and bone. Immunohistochemically, CD68-KP1 was the most commonly expressed marker, followed by CD33, myeloperoxidase, CD117, lysozyme, CD68-PGM1 and CD34. Of the patients, 26 (57.7%) presented with de novo MS, 7 (15.5%) had simultaneous acute myeloid leukaemia and 12 (26.8%) had a previous history of haematological disorders. Kaplan-Meier survival analysis revealed that the 2-year and 5-year overall survival (OS) rates were 46.4% and 39.8%, respectively; the median OS duration was 11 months. Increasing age had a negative prognostic relationship with survival (p = 0.04). Chromosomal abnormalities were detected in approximately 6/10 (60%) of paediatric patients and 6/9 (66.7%) of adult patients. t(8;21)(q22;q22) translocation was identified in 20% of paediatric patients.
CONCLUSIONS: MS diagnosis is usually challenging; an expanded immunohistochemical panel should be used for an accurate diagnosis. Although MS generally has a poor prognosis, increasing age appears to be associated with a worse outcome.

UNASSIGNED: Myeloid sarcoma (MS) is an extramedullary malignant tumor composed of immature myeloid cells. It occurs in patients with acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), or chronic myeloid leukemia (CML). MS may coincide with disease diagnosis or precede bone marrow involvement by months or even years; it can also represent the extramedullary manifestation of a relapse (1, 2).
UNASSIGNED: The aim of this study is to describe clinical characteristics of children diagnosed with MS in Poland as well as to analyze diagnostic methods, treatment, and outcomes including overall survival (OS), relapse-free survival (RFS), and event-free survival (EFS). The study also attempted to identify factors determining treatment outcomes.
UNASSIGNED: The study group comprised 43 patients (F=18, M=25) aged 0-18 years (median age, 10.0 years; mean age, 8.8 years) diagnosed with MS based on tumor biopsy and immunohistochemistry or identification of underlying bone marrow disease and extramedullary tumor according to imaging findings.
UNASSIGNED: The clinical data and diagnostic and therapeutic methods used in the study group were analyzed. A statistical analysis of the treatment outcomes was conducted with STATISTICA v. 13 (StatSoft, Inc., Tulsa, OK, USA) and analysis of survival curves was conducted with MedCalc 11.5.1 (MedCalc Software, Ostend, Belgium). Statistical significance was considered at p<0.05.
UNASSIGNED: In the study group, MS was most frequently accompanied by AML. The most common site of involvement was skin, followed by orbital region. Skin manifestation of MS was more common in the age group <10 years. The most frequent genetic abnormality was the t(8;21)(q22;q22) translocation. The 5-year OS probability (pOS), 5-year RFS probability (pRFS), and 5-year EFS probability (pEFS) were 0.67 ± 0.08, 0.79 ± 0.07, and 0.65 ± 0.08, respectively. In patients with isolated MS and those with concurrent bone marrow involvement by AML/MDS, pOS values were 0.56 ± 0.12 and 0.84 ± 0.09 (p=0.0251), respectively, and pEFS values were 0.56 ± 0.12 and 0.82 ± 0.08 (p=0.0247), respectively. In patients with and without the t(8;21)(q22;q22) translocation, pEFS values were 0.90 ± 0.09 and 0.51 ± 0.14 (p=0.0490), respectively.
UNASSIGNED: MS is a disease with a highly variable clinical course. Worse treatment outcomes were observed in patients with isolated MS compared to those with concurrent bone marrow involvement by AML/MDS. Patients with the t(8;21)(q22;q22) translocation were found to have significantly higher pEFS. MS location, age group, chemotherapy regimen, surgery, and/or radiotherapy did not have a significant influence on treatment outcomes. Further exploration of prognostic factors in children with MS is indicated.

UNASSIGNED: extramedullary acute myeloid leukemia (eAML) is characterized by extramedullary tumor formation infiltrated by myeloid blasts, with or without maturation and effaced architecture. The clinical, genetic and molecular aspects and overall outcomes are well defined worldwide, but not well characterized in our region.
UNASSIGNED: This is a retrospective single center cohort study on 32 patients, who were identified over 10 years to study the clinical, pathologic and genetic-molecular aspects, and survival outcomes.
UNASSIGNED: eAML is rare (1%), occurs at a younger age with male predominance. Central nervous system (CNS) with facial bone invasion is most commonly identified (34.4%). 45.5% were positive for conventional myeloid markers (MPO), CD33, CD117, and 36% positive for CD34 and CD68. 54% with normal karyotype had deleterious mutations on further testing. NGS revealed pathogenic mutations in 76%(N-9/17) and none tested positive for P53, IDH1 or IDH2. At a median follow up time of 43mo (range, 8.6-80mo); 37.5%(N-12) were in complete remission, 62.5%(N-20) relapsed. 28% of relapses were after allotransplant. 31%(N-10) alive and continued in complete remission(CR), and 69%(N-22) of patients have died.Median overall survival (OS) is 18.4 and relapse free survival (RFS) 18.7 months. OS and RFS were significantly better in patients, who attained CR after induction (IC 11.9 mo vs zero; P = 0.0001; IC 12mo vs zero; P = 0.0001) compared to patients with relapsed disease; and in patients who received allo-transplant consolidation with median OS and RFS 42 vs 8.5mo (P = 0.002) and 42months vs 10 mo (P = 0.006). Thus allotransplant may be considered for all eligible patients in first CR.
UNASSIGNED: achievement of complete remission after induction therapy is associated with improved outcomes in eAML. Allotransplant in first complete remission may be the most effective modality for achieving long-term remissions.

We performed a retrospective study describing the characteristics of myeloid sarcoma (MS) and evaluated the outcome of hematopoietic stem cell transplantation (HSCT) in patients with MS. There were 27 patients with de novo isolated MS, 34 with de novo leukemic MS and 13 with secondary leukemic MS in our study. Sixty-three patients received induction chemotherapy. Following induction therapy, 35 patients underwent HSCT, including 10 autogenous HSCT (auto-HSCT) and 25 allogeneic HSCT (allo-HSCT) cases. Compared with intensive chemotherapy only as consolidation treatment, HSCT (auto-/allo-HSCT) significantly improved the overall survival (OS) of MS patients (p < 0.05), while allo-HSCT also improved progression-free survival (PFS, p = 0.032). According to multivariate analysis, poorer prognosis in terms of OS was observed in older patients (p = 0.024, HR = 1.030, 95% CI 1.004-1.057), while HSCT (auto/allo-HSCT) had a favorable impact on OS for patients with MS (auto-HSCT, p = 0.044, HR = 0.201, 95% CI 0.042-0.959; allo-HSCT, p = 0.038, HR = 0.341, 95% CI 0.124-0.943). Extramedullary disease without complete remission (CR) after induction therapy was the sole variable independent of high OS and PFS (p = 0.049, HR = 2.243, 95% CI: 1.005-5.005; p = 0.017, HR = 2.535, 95% CI 1.180-5.448, respectively). The data indicate that HSCT is an effective treatment for patients with MS who have achieved CR of extramedullary disease after induction therapy.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been regarded as a potential strategy for myeloid sarcoma (MS). The previous reports focused mainly on matched sibling donor (MSD) or matched unrelated donor (MUD) transplantation. There are no reports on haploidentical HSCT (haplo-HSCT) in MS. We retrospectively reviewed 14 MS patients who underwent haplo-HSCT. All patients achieved complete donor engraftment. The median time for neutrophil engraftment and platelet engraftment were 10 (12-21) days and 18 (8-31) days. The 100-day cumulative incidence of grade II-IV acute graft-versus-host disease (GVHD) and 3-year cumulative incidence of chronic GVHD were 37.7% (95%CI, 23.2-52.1%) and 35.7% (95%CI, 22.2-49.2%). Cytomegalovirus (CMV) reactivation was documented in 86% patients, and only one patient developed CMV pneumonia. Treatment-related mortality occurred in one (7%) patient. The 1- and 3-year cumulative incidence of relapse was 21.4% (95%CI, 11.8-31.1%) and 35.7% (95%CI, 22.4-49.0%). The probability of overall survival at 1 and 3 years was 71.4% (95%CI, 51.3-99.5%) and 64.3% (95%CI, 43.5-95.0%), respectively. The probability of disease-free survival at 1 and 3 years was 71.4% (95%CI, 51.3-99.5%) and 57.1% (95%CI, 36.3-89.9%), respectively. In conclusion, haplo-HSCT is a feasible method for patients with MS who have no MSD or MUD.

BACKGROUND: Myeloid sarcoma (MS), also known as chloroma, is an extramedullary manifestation of malignant primitive myeloid cells. Previously, only small studies investigated clinical and imaging features of MS. The purpose of this study was to elucidate clinical and imaging features of MS based upon a multicenter patient sample.
METHODS: Patient records of radiological databases of 4 German university hospitals were retrospectively screened for MS in the time period 01/2001 and 06/2019. Overall, 151 cases/76 females (50.3%) with a mean age of 55.5 ± 15.1 years and 183 histopathological confirmation or clinically suspicious lesions of MS were included into this study. The underlying hematological disease, localizations, and clinical symptoms as well as imaging features on CT and MRI were investigated.
RESULTS: In 15 patients (9.9% of all 151 cases) the manifestation of MS preceded the systemic hematological disease. In 43 cases (28.4%), first presentation of MS occurred simultaneously with the initial diagnosis of leukemia, and 92 (60.9%) patients presented MS after the initial diagnosis. In 37 patients (24.5%), the diagnosis was made incidentally by imaging. Clinically, cutaneous lesions were detected in 35 of 151 cases (23.2%). Other leading symptoms were pain (n = 28/151, 18.5%), neurological deficit (n = 27/151, 17.9%), swelling (n = 14/151, 9.3%) and dysfunction of the affected organ (n = 10/151, 6.0%). Most commonly, skin was affected (n = 30/151, 16.6%), followed by bone (n = 29/151, 16.0%) and lymphatic tissue (n = 21/151, 11.4%). Other localizations were rare. On CT, most lesions were homogenous. On T2-weighted imaging, most of the lesions were hyperintense. On T1-weighted images, MS was hypointense in n = 22/54 (40.7%) and isointense in n = 30/54 (55.6%). A diffusion restriction was identified in most cases with a mean ADC value of 0.76 ± 0.19 × 10- 3 mm2/s.
CONCLUSIONS: The present study shows clinical and imaging features of MS based upon a large patient sample in a multicenter design. MS occurs in most cases meta-chronous to the hematological disease and most commonly affects the cutis. One fourth of cases were identified incidentally on imaging, which needs awareness of the radiologists for possible diagnosis of MS.

BACKGROUND: The diagnosis of myeloid sarcoma (MS) in cytology samples is challenging, especially when these tumors occur prior to a diagnosis of acute myeloid leukemia. The aim of this study was to review our cytopathology service\'s experience with a series of MS cases.
METHODS: Archival records were searched from which 16 cytology cases of MS were identified and reviewed. Clinical findings, cytomorphology, and ancillary studies were analyzed.
RESULTS: MS was secondary to acute myeloid leukemia in 14 cases, chronic myeloid leukemia (CML) in blast crisis in 1 case, and myelodysplastic syndrome in another. Flow cytometry was supportive in 11 cases, immunostains were helpful when performed in 4 cases, and fluorescence in-situ hybridization in the CML case showed t(9;22). Cellularity was variable in all leukemia subtypes. Blasts had round or cleaved nuclei with indistinct nucleoli. Maturing granulocytes were present only in the patient with CML, or with peripheral blood contamination (4 cases). Other blood precursors were absent. Apoptosis and lymphoglandular bodies were present in almost one-half of the cases, which correlated with increased blasts. Mitoses were infrequent (6 cases) and necrosis was not seen.
CONCLUSIONS: The diagnosis of MS in cytology specimens can be made in cases with adequate cellularity and supportive ancillary studies in the correct clinical context. MS was harder to diagnose in cytology cases with low cellularity, blood contamination, and few blasts. Cytologic features that pose diagnostic pitfalls are lymphoglandular bodies suggestive of lymphoma and maturing or mixed granulocytes that mimic infection.