Myeloid Sarcoma Research Articles (Page 1)

Epidemiology, clinical features, and molecular basis of TTMV::RARA-driven acute promyelocytic leukemia.

Extramedullary blast crisis (EMBC) is rare, clinically heterogeneous, and often misdiagnosed because routine histology may be inconclusive. We describe a CML-EMBC case in which targeted RNA sequencing uncovered concurrent NPM1::CCDC28A and BCR::ABL1 fusions, refining the diagnosis and suggesting a novel molecular subset.Clinical, laboratory, imaging, histopathology, and outcome data of a 26-year-old man were reviewed retrospectively. Targeted RNA-seq was performed on formalin-fixed, paraffin-embedded sacrococcygeal tissue. PubMed and Google Scholar were searched with "NPM1," "CCDC28A," "fusion," "CML," "myeloid sarcoma," and "extramedullary blast crisis" to contextualise NPM1 rearrangements. The patient achieved deep molecular remission of chronic-phase CML (BCR::ABL1 0.0058% International Scale) while receiving flumatinib, yet developed a painful sacrococcygeal mass. Initial biopsy suggested an undifferentiated small round-cell sarcoma. RNA-seq revealed dual NPM1::CCDC28A and BCR::ABL1 fusions, prompting reclassification as granulocytic sarcoma-type CML-EMBC. Intermediate-dose cytarabine with continued tyrosine-kinase inhibition produced marked metabolic regression on PET-CT, and the patient has been bridged to allogeneic hematopoietic stem-cell transplantation. Literature review uncovered only sporadic reports of NPM1::CCDC28A; experimental data indicate that the fusion up-regulates HOX clusters similarly to mutant NPM1, facilitating leukemogenesis and extramedullary dissemination. Solitary tumours in CML patients who are in marrow remission should prompt suspicion for EMBC. When morphology is ambiguous, integrating molecular pathology, particularly targeted RNA-seq, can confirm myeloid lineage and uncover disease-relevant alterations. Co-occurrence of BCR::ABL1 and NPM1::CCDC28A may delineate a distinct EMBC subset with prognostic and therapeutic relevance. Prospective studies are required to clarify the fusion's pathogenic role and biomarker potential.

Vaginal Myeloid Sarcoma: A Rare Extramedullary Presentation of a Myeloid Neoplasm

S3813 Beyond the Bone Marrow: Anorectal Granulocytic Sarcoma Presenting as GI Bleeding

Acute myeloid leukemia (AML) is a malignancy characterized by the uncontrolled proliferation of immature hematopoietic cells, leading to the infiltration of various tissues. Ocular involvement in AML is rare and typically associated with a poor prognosis. A 1-year-old infant with no significant medical history presented with rapidly progressive bilateral proptosis, more pronounced on the left side, over a 15-day period. Ophthalmological examination revealed painful, inflammatory proptosis and stage 2 bilateral papilledema. CT scans indicated diffuse infiltration of the orbital and extraconical spaces, along with proptosis. Blood tests showed pancytopenia, and a myelogram confirmed the diagnosis of AML. Unfortunately, the child's condition deteriorated due to severe sepsis, leading to death following hospitalization in the pediatric ICU. Ocular involvement in acute leukemia is uncommon but may present as chloroma or granulocytic sarcoma, typically manifesting as rapidly progressive unilateral or bilateral exophthalmos. This can be mistaken for conditions such as rhabdomyosarcoma or infection. The presence of leukemia in the oculo-orbital region is a poor prognostic indicator, as it is considered a central nervous system disorder and should be managed accordingly. The prevalence of ocular involvement has significantly decreased with the advent of appropriate chemotherapy.

Abstract Acute myeloid leukemia (AML) is a heterogeneous disorder characterized by the proliferation of myeloid progenitor cells infiltrating the bone marrow. Myeloid sarcoma is an extramedullary malignancy that can occur in soft tissue, bone, lymph nodes however CNS involvement is rare. 68-year-old female with past medical history of breast cancer s/p left-sided mastectomy in 2014 and tamoxifen therapy for seven years that presented to the ED for altered mental status, and headache that was ongoing for the past several days with associated significant weight loss, and easy bruising. CT brain revealed stable late subacute to chronic bilateral subdural hematomas with small area of more recent hemorrhage on the left; left to right shift of 2mm noted. MRI brain revealed bilateral subdural fluid collection; mass effect from larger left collection resulting in rightward midline shift of 3mm. Significant labs was noted for a leukocytosis 73,000, normochromic normocytic anemia, thrombocytopenia, and elevation of immature cells of promyelocytes myelocytes, metamyelocytes, and blasts. Flow cytometry revealed leukocytosis with blasts greater than 40% consistent with AML. Bone marrow aspirate revealed AML, non-M3. Molecular genetics revealed FLT3-ITD negative. Cytogenetics revealed abnormal karyotype with Trisomy 8. Over the patient’s hospital course, the patient became progressively obtunded. Repeat imaging showed stable size of bilateral subdural hemorrhages with a stable mass effect but increased cerebral edema and crowding of the basilar cisterns. Neurosurgery emergently performed a right parietal burr hole with evacuation of the chronic subdural hematoma and placement of a subdural drain. During the procedure, a left parietal craniotomy had to also be performed after an extra-axial parietal mass was incidentally found. Pathology of the brain mass revealed acute myeloid leukemia. The patient was transferred to a tertiary care center for plans of induction chemotherapy. Intracranial myeloid sarcoma is a rare manifestation of AML with an incidence of 0.4%. Oftentimes intracranial myeloid sarcoma is detected during routine CT/MRI studies given acute neurological symptoms. However in our case, initial imaging showed the acute subdural hematomas, and the mass was found incidentally during surgery. Risk factors associated with AML include genetic disorders such as Trisomy 8 which is found from cytogenetic testing. Trisomy 8 is one of the most common cytogenetic alterations found in patients’s with AML due to the association with mutations in DNA methylation causing a stronger predisposition to the pathogenesis of leukemia with a reported frequency noted to be between 10-15%. It has been noted that the prognosis of Trisomy 8 with AML has a shorter median overall survival, and is classified as an intermediate risk AML. Treatment includes surgical intervention to relieve the mass effect, and also aides with the histopathologic diagnosis. In addition the use of adjuvant radiotherapy or chemotherapy significantly reduced mortality. Citation Format: Bianca Vahia, Ram Hirpara, Danilo Frias, Ahmed Behairy. A case of intracranial myeloid sarcoma discovered after a subdural hematoma [abstract]. In: Proceedings of the 18th AACR Conference on the Science of Cancer Health Disparities; 2025 Sep 18-21; Baltimore, MD. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2025;34(9 Suppl):Abstract nr C082.

Myeloid sarcoma (MS) is a mass‐forming extramedullary manifestation of myeloid blasts, either in relation to an underlying acute myeloid leukemia (AML), another myeloid neoplasm (MN) or as a de novo occurrence. Data on the genetic profile of MS are sparse. In this study, 41 MS of 34 patients, including 7 de novo cases and 24 patients with antecedent or synchronous MN, were analyzed with targeted next‐generation sequencing (NGS), RNA‐based fusion detection, and gene expression profiling (GEP). In 10 patients, a MS developed after stem cell transplantation for MN. Additionally, 21 available pre‐transplant bone marrow biopsies (BMB) from 20 patients and 6 post‐transplant BMB from 6 patients were investigated. The most frequently mutated gene was TET2 (41%), followed by NPM1 (38%) and NRAS (35%). Overall, 74% of the cases exhibited mutations affecting the MAPK/ERK pathway. AML‐type fusions were detected in seven MS patients, who were younger than those without fusions (median 49 versus 67 years). Nine of 13 patients with a MN and available pre‐transplant BMB showed additional mutations restricted to the MS, including an additional NRAS mutation in 3/5 cases with AML. Five of seven of patients with pre‐transplant BMB without evidence of a MN revealed clonal hematopoiesis (CH), mostly shared TET2 mutations. Comparative GEP between BM and MS revealed upregulation of the MAPK/ERK pathway in MS and of gene sets relevant for interaction with the microenvironment. In conclusion, MS is characterized by a high incidence of MAPK/ERK pathway mutations and activation, frequent clonal evolution, and association with CH in elderly patients without recurrent AML‐type fusions.

Myeloid sarcoma presenting initially in the oral cavity under non-leukemic conditions: A case report

Myeloid Sarcoma with a PICALM–MLLT10 Fusion Presenting as an Isolated Mediastinal Mass in a Middle-Aged Asian Male: A Case Report

Myeloid sarcomas of the genitourinary tract: A multi-institutional study of sixteen tumors with review of literature.

To analyze symptoms, imaging features, management, and outcomes of musculoskeletal myeloid sarcoma in adult leukemic patients. This is a retrospective analysis of clinical symptoms, imaging features, management, and outcomes in 41 adult leukemic patients with biopsy-proven myeloid sarcomas of bones and muscles. Nineteen patients had acute, and 15 had chronic myeloid leukemia. Additional 5 previously treated leukemia patients included 1 with chronic myeloid leukemia, 3 with myelofibrosis, and 1 with myelodysplastic syndrome. The remaining 2 patients had isolated myeloid sarcoma with normal marrow without a history of hematologic disorder. Twenty-nine patients had bone tumors only, 3 muscle tumors only, 8 both bone and soft tissue tumors, and 1 intraarticular synovial tumor of an ankle. Of the 71 focal bone tumors, 68 were lytic and 3 were sclerotic. In addition, diffuse sclerotic bone lesions were present in 1 patient, and diffuse mixed lytic/sclerotic bone lesions in 2 patients. Most tumors were asymptomatic and were discovered incidentally on imaging. Local pain, mass, and pathologic fractures were the most common complaints when present. Vertebral bone and paravertebral soft tissue tumors caused neurological symptoms. Muscle tumors became symptomatic when they involved adjoining bone, nerve, or spinal cord. Only 3 among 13 muscle tumors presented as palpable masses. The imaging features of these musculoskeletal tumors were nonspecific. On MRI, both muscle and lytic bone MSs were hypo-to-iso-intense on T1WI, hyperintense on fat-suppressed T2WI, and enhanced on post-contrast fat-suppressed T1WI. A synovial myeloid sarcoma of the ankle showed diffusely thickened synovium on MRI. F-18 FDG PET-CT was helpful in the detection, monitoring of treatment response, and post-treatment surveillance in 5 patients. All patients were treated with cytarabine-based systemic anti-leukemic treatment and optional radiation, surgical resection, bone marrow transplant, and/or a combination of these. The known mean survival time of 35 dead patients after the appearance of musculoskeletal MS was 12.1 months. Musculoskeletal myeloid sarcoma, which can occasionally precede it, is a rare complication of AML. Most tumors are asymptomatic. Imaging, particularly MRI and 18-F FDG PET-CT, plays a crucial role in detecting and monitoring treatment response, as well as post-treatment surveillance. The disease has poor clinical outcomes and short-term survival.

An Unusual Case of Multiple Gastric Masses: Granulocytic Sarcoma.

A case of leukemic cervical myeloid sarcoma

Introduction: Acute Myeloid Leukemia (AML) is a hematologic malignancy characterized by the clonal expansion of myeloid progenitors. While it primarily affects the bone marrow, extramedullary relapse occurs in 3–5% of cases, and it is linked to poor prognosis. Central nervous system (CNS) involvement presents diagnostic challenges due to nonspecific symptoms. CNS manifestations include leptomeningeal dissemination, nerve infiltration, parenchymal lesions, and myeloid sarcoma, occurring at any disease stage and frequently asymptomatic. Methods: A 62-year-old man with a recent history of AML in remission presented with diplopia and aching paresthesias in the left periorbital region spreading to the left frontal area. The diagnostic workup included neurological and hematological evaluation, lumbar puncture, brain CT, brain magnetic resonance imaging (MRI) with contrast, and dermatological evaluation with skin biopsy due to the appearance of nodular skin lesions on the abdomen and thorax. Results: Neurological evaluation showed hypoesthesia in the left mandibular region, consistent with left trigeminal nerve involvement, extending to the periorbital and frontal areas, and impaired adduction of the left eye with divergent strabismus in the primary position due to left oculomotor nerve palsy. Brain MRI showed an equivocal thickening of the left oculomotor nerve without enhancement. Cerebrospinal fluid (CSF) analysis initially showed elevated protein (47 mg/dL) with negative cytology; a repeat lumbar puncture one week later detected leukemic cells. Skin biopsy revealed cutaneous AML localization. A diagnosis of AML relapse with CNS and cutaneous localization was made. Salvage therapy with FLAG-IDA-VEN (fludarabine, cytarabine, idarubicin, venetoclax) and intrathecal methotrexate, cytarabine, and dexamethasone was started. Subsequent lumbar punctures were negative for leukemic cells. Due to high-risk status and extramedullary disease, the patient underwent allogeneic hematopoietic stem cell transplantation. Post-transplant aplasia was complicated by septic shock; the patient succumbed to an invasive fungal infection. Conclusions: This case illustrates the diagnostic complexity and poor prognosis of extramedullary AML relapse involving the CNS. Early recognition of neurological signs, including cranial nerve dysfunction, is crucial for timely diagnosis and management. Although initial investigations were negative, further analyses—including repeated CSF examinations and skin biopsy—led to the identification of leukemic involvement. Although neuroleukemiosis cannot be confirmed without nerve biopsy, the combination of clinical presentation, neuroimaging, and CSF data strongly supports the diagnosis of extramedullary relapse of AML. Multidisciplinary evaluation remains essential for detecting extramedullary relapse. Despite treatment achieving CSF clearance, the prognosis remains unfavorable, underscoring the need for vigilant clinical suspicion in hematologic patients presenting with neurological symptoms.

ABSTRACTPurposeThis study examines the protein expression and mRNA levels of myeloperoxidase (MPO) in patients with Kikuchi's disease, and explores the association between the MPO‐463G/A polymorphism and Kikuchi's disease.MethodsParaffin blocks from 43 patients with Kikuchi's disease were collected, and paraffin blocks from patients with reactive hyperplastic lymph nodes, granulomatous inflammation, and myeloid sarcoma were used as controls. Immunohistochemistry (IHC), quantitative reverse transcription polymerase chain Reaction (qRT‐PCR) and Sanger sequencing were used to detect the relevant variants.ResultsThe positive rate of MPO protein expression in the Kikuchi's disease group was 100% by IHC. In comparison to the control group, patients with Kikuchi's disease exhibited elevated MPO mRNA expression levels, which demonstrated a positive correlation with protein expression levels. Kikuchi's disease and reactive hyperplastic lymph nodes displayed distinct genotypes at the MPO‐463 locus, with mutation phenotypes of 7% and 30%, respectively. The G allele at this locus emerged as a risk factor.ConclusionsIn Kikuchi's disease, both the protein and mRNA expression levels of MPO are elevated, and the high expression of mRNA is positively correlated with the protein expression levels. The polymorphism at the MPO‐463 locus may be associated with the occurrence of Kikuchi's disease.

Early Relapse with Isolated Myeloid Sarcoma in a Patient Diagnosed Acute Myeloid Leukemia with FLT3- D835Y Mutation

Myeloid sarcoma is a rare extramedullary tumor of immature myeloid cells that is often associated with acute myeloid leukemia (AML). We herein report an 81-year-old man who presented with intestinal obstruction due to myeloid sarcoma of the small intestine. Diagnostic challenges were overcome using double-balloon enteroscopy and a biopsy, which confirmed the diagnosis of myeloid sarcoma. The patient subsequently developed AML but responded well to chemotherapy. This case underscores the importance of considering myeloid sarcoma in the differential diagnosis of small-bowel tumors. Highlighting the significance of a histological analysis, even in patients presenting with small bowel obstruction, the early diagnosis and treatment are crucial for improving outcomes, particularly in patients without a history of hematologic malignancies.

68Ga-CXCR4 PET/CT was performed in a patient with acute myeloid leukemia (AML) and granulocytic sarcoma in the left cervical region, who had previously undergone 18F-FDG PET/CT. Compared with 18F-FDG PET/CT, 68Ga-CXCR4 PET/CT revealed a greater number of malignant lymph nodes with more intense uptake in both supradiaphragmatic and infradiaphragmatic regions. Furthermore, markedly increased radiotracer uptake was observed in the bone marrow and spleen compared with FDG. This case underscores the superior sensitivity of 68Ga-CXCR4 PET/CT in detecting AML infiltration and supports further investigation of CXCR4-targeted imaging and therapeutic approaches in high-risk AML.

Myeloid sarcoma (MS) is a rare hematologic tumor of immature myeloid cells with lesions located outside the bone marrow. The disease can develop de novo as extramedullary myeloid tumor, be a manifestation of acute myeloid leukemia (AML) or be diagnosed as an AML relapse after previously achieved remission. MS occurs in all age groups, although more commonly in elderly people. Diagnosis is based on immunomorphological and molecular genetic analyses of the tumor tissue. The most effective treatment regimens in MS are those used for AML therapy with subsequent allogeneic hematopoietic stem cell transplantation provided that the first complete remission was achieved. In addition to that, radiotherapy as well as biological and targeted drugs are administered. Nevertheless, the prognosis of the disease remains generally unfavorable. The present paper reports a clinical case of MS with KRAS mutation, tumor skin and Th5–Th6 lesions, spinal cord compression, and developing flaccid paraplegia. The patient received chemotherapies of varying intensity as well as hypomethylating agents combined with venetoclax and the targeted drug trametinib. The course of the disease was complicated by secondary hemophagocytic syndrome (SHS). The present case report demonstrates the challenges of both diagnosis and treatment of this rare and poor-prognosis extramedullary myeloid tumor complicated by SHS.

ABSTRACTGastric myeloid sarcoma (MS) is a rare disease with numerous endoscopic manifestations and is typically diagnosed on the basis of immunohistochemistry. However, the epidemiology, treatment, and prognosis of gastric MS remain controversial. The goal of this study is to preliminarily analyze these controversial aspects of gastric MS.