Extramedullary myeloid cell tumors in acute nonlymphocytic leukemia: a clinical review

Acute myeloid leukemia with peripheral lymph node involvement in dogs: A retrospective study of 23 cases

Acute myeloid leukemia (AML) can infiltrate extramedullary tissues, such as the liver, spleen, and lymph nodes and can be difficult to differentiate from lymphoma in cytologic and histologic specimens. Our goal was to identify cytologic features that would support a diagnosis of AML in peripheral lymph node aspirates, for which we used the term extramedullary AML (eAML). Medical records of 23 dogs with a diagnosis of AML and archived lymph node aspirate smears from 2016 to 2024 were reviewed across 4 institutions. Inclusion criteria included ≥50% myeloid blasts plus differentiating myeloid cells in lymph node smears, confirmation of myeloid lineage by flow cytometric analysis, and complete medical records. Peripheral lymphadenopathy was the reason for presentation (9/23, 39%) or was found incidentally on physical examination (14/23, 61%). Most dogs were bi- or pancytopenic (18/23, 78%), with blasts identified in blood smears of 18 dogs (78%). Initial lymph node aspirate interpretations included hematopoietic neoplasia (8/21, 38%), AML (6/21, 29%), lymphoma (5/21, 24%), lymphoid hyperplasia (1/21, 5%), and granulocytic precursor infiltrates (1/21, 5%). On lymph node smear review, cytologic features supporting an eAML were differentiating granulocytes, blasts with myeloid features or promonocytes, dysplastic changes in myeloid cells, and retention of residual lymphocytes. The median survival was 22 days (range = 1-360 days), and 69% of 16 dogs given chemotherapy or glucocorticoids lived for 30 days or more. Our study highlights the importance of hemogram results and lymph node aspirate smear examination for morphologic features of myeloid differentiation to help diagnose eAML in lymph node smears.

Diagnostic Approaches in Myeloid Sarcoma

Myeloid sarcoma (MS), or extramedullary acute myeloid leukaemia tumour (eAML), is a rare hematopoietic neoplasm. Recognised as a distinct entity within acute myeloid leukaemia (AML), MS presents significant diagnostic challenges due to its rarity, clinical heterogeneity, and variable immunophenotypic and genetic characteristics. The mechanisms by which leukaemic stem cells (LSCs) migrate to form solid tumours in extramedullary (EM) sites remain unclear. MS can occur de novo, precede AML, and manifest alongside AML relapse. It can also develop with myelodysplastic syndromes (MDSs) or myeloproliferative neoplasms (MPNs). MS frequently presents in organs such as the skin, lymph nodes, gastrointestinal (GI) tract, and central nervous system (CNS), often resulting in diverse clinical manifestations. Diagnosis relies on a comprehensive approach, including tissue biopsy, bone marrow (BM) evaluation, and advanced imaging modalities. Accurate diagnosis is crucial for risk stratification and treatment selection. Prognosis is influenced by several factors: MS's anatomical location, timing of MS diagnosis, genetic profile, and possible treatment. This review emphasises the need for comprehensive diagnostic methods to better define individual MS characteristics and prognosis. It explores the role of novel targeted therapies in improving patient outcomes and further highlights the critical need for future multicentre data collection to optimise diagnostic and therapeutic approaches.

A fatal case of peritonitis due to colonic localization of acute myeloid leukemia

Myeloid sarcoma (MS) is an extramedullary localization of immature granulocyte cells that can occur in association with acute myeloid leukemia (AML). Gastrointestinal involvement is relatively common in MS, but exclusive colonic localization is a rare occurrence. Here, we report on a 53-year-old male patient affected by AML developing a severe abdominal pain caused by intestinal perforation requiring surgical intervention. The post-mortem examination revealed an infiltrate consistent with MS. Diagnosis of colonic MS can be difficult due to non-specific symptoms and complicated by the challenges associated with exploring this area. Clinical acumen is crucial to promptly establish adequate management due to the potentially life-threatening nature of this condition.

Cervical Granulocytic Sarcoma Without Acute Leukemia: A Case Report and Review of 42 Additional Cases

Granulocytic sarcoma (GS), also known as extramedullary myeloid tumor, is a rare malignant neoplasm composed of immature myeloid cells. Although it is most commonly associated with acute myeloid leukemia (AML), a subset of GS cases can occur prior to the development of AML. GS can present in a variety of extramedullary locations, including bone, skin, lymph nodes, and the female reproductive system. We report the case of a 45-year-old Asian female patient who presented to our hospital in July 2015 with a three-month history of left-sided lumbago. A contrast-enhanced computed tomography (CT) scan of the abdomen and pelvis revealed a retroperitoneal mass and an enlarged uterine cervix with an accompanying 57×52 mm mass. A cervical biopsy confirmed the diagnosis of GS. Immunohistochemical (IHC) analysis of the biopsy showed that the neoplastic cells were positive for CD34, CD15, CD33, CD43, lysozyme, and myeloperoxidase. The patient was subsequently treated with an idarubicin and cytarabine-based regimen for four cycles. A follow-up CT scan of the abdomen and pelvis demonstrated a significant reduction in the size of the previous lesions. Unfortunately, the patient passed away in April 2016 due to a cerebral hemorrhage. In this report, we also review 42 additional cases to discuss the pathological characteristics, treatment strategies, and clinical outcomes of GS.

PET/CT in leukemia: utility and future directions

2-Deoxy-2-[ 18 F]fluoro- d -glucose PET/computed tomography ([ 18 F]FDG PET/CT) has proven to be a sensitive method for the detection and evaluation of hematologic malignancies, especially lymphoma. The increasing incidence and mortality rates of leukemia have raised significant concerns. Through the utilization of whole-body imaging, [ 18 F]FDG PET/CT provides a thorough assessment of the entire bone marrow, complementing the limited insights provided by biopsy samples. In this regard, [ 18 F]FDG PET/CT has the ability to assess diverse types of leukemia The utilization of [ 18 F]FDG PET/CT has been found to be effective in evaluating leukemia spread beyond the bone marrow, tracking disease relapse, identifying Richter's transformation, and assessing the inflammatory activity associated with acute graft versus host disease. However, its role in various clinical scenarios in leukemia remains unacknowledged. Despite their less common use, some novel PET/CT radiotracers are being researched for potential use in specific scenarios in leukemia patients. Therefore, the objectives of this review are to provide a thorough assessment of the current applications of [ 18 F]FDG PET/CT in the staging and monitoring of leukemia patients, as well as the potential for an expanding role of PET/CT in leukemia patients.

Case report: Clinical features of pediatric acute myeloid leukemia presenting with cardiac tamponade: a case series study and literature review

Objective

This study aims to elucidate the clinical features observed in cases of pediatric acute myeloid leukemia (AML) initially presenting with cardiac tamponade and to share treatment experiences.

Materials and methods

Five pediatric patients were initially diagnosed with AML accompanied by cardiac myeloid sarcoma (MS). The diagnosis was established by examining our hospital records and reviewing pertinent literature from 1990 to July 2023, accessible through MEDLINE/PubMed. We comprehensively assessed the clinical characteristics and treatment modalities employed for these patients.

Result

Five pediatric patients presented with acute symptoms, including shortness of breath, malaise, cough, and fever, leading to their hospitalization. Physical examination revealed irritability, hypoxia, tachypnea, tachycardia, and hypotension. Initial detection utilized chest X-ray or echocardiogram, leading to subsequent diagnoses based on pericardial effusion and/or bone marrow examination. Two patients received chemotherapy at the time of initial diagnosis, one with cytarabine and etoposide, and the other with cytarabine and cladribine. Post-treatment, their bone marrow achieved remission, and over a 2.5-year follow-up, their cardiac function remained favorable. Unfortunately, the remaining three patients succumbed within two weeks after diagnosis, either due to receiving alternative drugs or without undergoing chemotherapy.

Conclusion

This is the first and largest case series of pediatric AML patients with cardiac MS, manifesting initially with cardiac tamponade. It highlights the rarity and high mortality associated with this condition. The critical factors for reducing mortality include identifying clinical manifestations, conducting thorough physical examinations, performing echocardiography promptly, initiating early and timely pericardial drainage, and avoiding cardiotoxic chemotherapy medications.

Gastric myeloid sarcoma mimicking pseudoachalasia in non-leukemic context: a singular case report

Introduction and importance

Myeloid sarcoma (MS) is a rare tumour associated with acute myeloid leukaemia (AML) and occasionally occurs independently. It typically affects skin, bone, lymph nodes, and rarely the gastrointestinal tract, with gastric cases being extremely rare. Notably, no reported instances associate pseudoachalasia with gastric myeloid sarcoma.

Case presentation

A 20-year-old male presented with severe dysphagia, refractory vomiting, and weight loss. Diagnosed with type III achalasia via oesophageal tests, subsequent gastroscopy revealed a large gastric mass, later identified as gastric myeloid sarcoma through histopathology.

Clinical discussion

MS, characterized by immature blast cells, poses diagnostic challenges without typical leukaemia symptoms. Diagnosis involves immunohistochemistry, employing markers like CD33, CD34, and CD43. Optimal treatments, such as chemotherapy or stem cell transplantation, aim to delay leukaemia progression. Gastric primary de-novo myeloid sarcoma is exceedingly rare, emphasizing the need for tailored treatment strategies.

Conclusion

Gastric myeloid sarcoma is an exceptionally rare tumour, especially without concurrent acute myeloid leukaemia (AML), complicating its diagnosis. This case represents the first globally documented instance of gastric myeloid sarcoma causing pseudoachalasia. Documenting this unique clinical presentation is crucial for a better grasp of gastric myeloid sarcoma's diverse manifestations.

Pancreatic Myeloid Sarcoma Causing Obstructive Jaundice: A Case Report and Literature Review

Myeloid sarcoma (MS) is an extramedullary manifestation of acute myeloid leukemia (AML) and commonly occurs in sites such as the lymph nodes, skin, soft tissues, and bone. It more rarely manifests in the pancreas, with less than 20 cases reported in the literature since 1987. Despite its rarity, MS should be considered in the differential diagnosis of a soft tissue mass causing obstructive jaundice, especially if the patient has a known hematologic disease. Isolated cases of pancreatic MS have been known to progress to AML; therefore, it is crucial to differentiate MS from more common diagnoses, such as pancreatic cancer or pancreatitis. This is a case of a 70-year-old male with symptomatic obstructive jaundice secondary to pancreatic MS, ultimately requiring endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP) for diagnosis and management. Also included is a comprehensive review of previous case reports with similar clinical presentations, management, and treatment of pancreatic MS.

Pretransplant hepatomegaly is linked to relapse in patients with leukemia and myelodysplastic syndrome not in remission

Hepatomegaly is an extramedullary disease (EMD) manifestation of hematological malignancy. Although EMD before allogeneic hematopoietic stem cell transplantation (allo-HCT) is a risk factor for relapse in patients not in complete remission (NonCR) patients, the significance of hepatomegaly to allo-HCT is unclear. We conducted a single-center retrospective observational study of 140 patients with acute leukemia and myelodysplastic syndrome who underwent allo-HCT at our institution from 2014 to 2019. Hepatomegaly was assessed by ultrasonography using the liver index (LI). In the univariable analysis, the LI/height ratio was significantly associated with relapse (hazard ratio [HR] per standard deviation [sd]: 1.51, 95% confidence interval [CI] 1.18-1.93, p = 0.001, sd = 13.8) in NonCR patients (n = 62), but showed no significant association in CR patients (n = 78) (HR per sd: 0.95, 95% CI 0.64-1.39, p = 0.780, sd = 8.7). In multivariable analysis, the LI/height ratio was significantly associated with relapse (HR per sd: 1.34, 95% CI 1.02-1.78, p = 0.037) after adjusting for the refined disease risk index and conditioning intensity. Interaction analysis showed a noteworthy but not statistically significant association between the LI/height ratio and CR status (p = 0.110). In conclusion, our findings suggest that the LI may be a risk factor for relapse in NonCR patients after allo-HCT.

Organomegalies as a predictive indicator of leukemia cutis in patients with acute myeloid leukemia

BACKGROUND

Leukemia cutis (LC) is an extramedullary acute myeloid leukemia (AML) infiltrate. No previous study has described the clinical characteristics and outcomes of Thai patients diagnosed with AML with LC.

MATERIALS AND METHODS

We conducted a 7-year retrospective case-control study on Thai AML patients at Siriraj Hospital from November 2013 to July 2020. Patients were divided into LC and non-LC groups. Initial clinical presentations and laboratory findings were examined to identify LC-associated factors. Overall survival (OS) and relapse-free survival (RFS) were assessed. Pathological tissues underwent re-evaluation to validate the LC diagnoses.

RESULTS

The study included 159 patients in a 2:1 ratio (106 non-LC and 53 LC). The LC group had a mean ± SD age of 54.3 ± 15.5 years; females were predominant. Three-fifths of the LC patients had intermediate-risk cytogenetics; 20.4% had an adverse risk, and 10.2% had a favorable risk. Most were classified as AML-M4 and AML-M5. Leukemic nodules were the primary finding in 58.5% of the cases, mainly on the legs. In the multivariate analysis of predictive factors associated with LC, organomegalies, specifically hepatomegaly, and lymphadenopathy, remained significant factors associated with LC [OR 4.45 (95%CI 1.20, 16.50); p = 0.026 and OR 5.48 (95%CI 1.65, 18.20); p = 0.005], respectively. The LC group demonstrated a significantly reduced OS (log-rank test p = 0.002) (median OS of 8.6 months vs. 32.4 months). RFS was considerably lower in the LC group (log-rank test p = 0.001) (median duration of 10.3 months vs. 24.4 months in the non-LC).

CONCLUSIONS

AML patients who developed LC tended to experience notably poorer prognoses. Therefore, it is imperative to consider aggressive treatment options for such individuals. The presence of organomegalies in AML patients serves as a strong predictor of the possible occurrence of LC when accompanied by skin lesions.

Nasopharyngeal myeloid sarcoma as a manifestation of acute monomyelocytic leukaemia

This case report describes the case of a man in his seventies presenting with a nasopharyngeal deposit of myeloid sarcoma associated with acute monomyelocytic leukaemia. He presented with right nasal obstruction associated with unilateral pulsatile tinnitus. CT and MRI scans of sinuses identified a moderately restricting mucosal swelling of the right torus tubarius, and a biopsy of the lesion diagnosed a nasal deposit of myeloid sarcoma.

Myeloid sarcoma and pathological fracture: a case report and review of literature

Myeloid sarcoma is a rare clinical entity that presents as an isolated proliferation of leukemic cells, concurrently with or at relapse of acute myeloid leukemia (AML), myelodysplastic syndromes/neoplasms (MDS), chronic myeloid leukemia (CML), and myeloproliferative neoplasm (MPN). Myeloid sarcoma disrupts the normal architecture of its surrounding tissues. When it forms in long bones, it can cause their pathological fracture. We recently experienced a rare case of MDS presenting with myeloid sarcoma in the femur that eventually resulted in its pathological fracture. Detailed chromosomal analysis of the bone marrow cells suggested emergence of myeloid sarcoma during the fast-paced progression of MDS just after acquiring trisomy 22. A comprehensive review of previous cases of myeloid sarcoma-associated pathological fracture indicated possible involvement of structural rearrangements of chromosomes 9 and 22. Management of myeloid sarcoma should continue to improve, and clinicians should note that myeloid sarcoma with specific chromosomal alterations needs extra medical attention to prevent pathological fracture.

Acute pancreatitis as the initial manifestation of acute myeloid leukemia with chromosome 16 rearrangements

Acute pancreatitis is an acute inflammatory process of the pancreas that is becoming an increasingly common clinical issue. The most frequent underlying etiologies include gallstones and chronic alcohol use, which account for more than two-thirds of cases. We recently experienced a rare case of acute myeloid leukemia (AML) presenting with recurrent acute pancreatitis, which we later discovered was caused by diffusely infiltrating extramedullary sarcoma in the pancreas. Comprehensive analysis of previous cases of AML presenting as acute pancreatitis suggested involvement of cytogenetic alterations in chromosome 16 in its pathogenesis. Further improvement in management of acute pancreatitis is needed, and clinicians should note that this occasionally fatal condition can be the initial and only manifestation of AML. In practice, prompt initiation of intensive chemotherapy is critical for treating such cases of AML-induced acute pancreatitis.

Myeloid sarcoma: more and less than a distinct entity

Myeloid sarcoma (MS) is a distinct entity among myeloid neoplasms defined as a tumour mass of myeloid blasts occurring at an anatomical site other than the bone marrow, in most cases concomitant with acute myeloid leukaemia (AML), rarely without bone marrow involvement. MS may also represent the blast phase of chronic myeloproliferative neoplasms (MPN) and myelodysplastic syndromes (MDS). However, the clinical and molecular heterogeneity of AML, as highlighted by the 2022 World Health Organization (WHO) and International Consensus (ICC) classifications, indirectly define MS more as a set of heterogeneous and proteiform diseases, rather than a homogeneous single entity. Diagnosis is challenging and relies mainly on histopathology, immunohistochemistry, and imaging. Molecular and cytogenetic analysis of MS tissue, particularly in isolated cases, should be performed to refine the diagnosis, and thus assign prognosis guiding treatment decisions. If feasible, systemic therapies used in AML remission induction should be employed, even in isolated MS. Role and type of consolidation therapy are not univocally acknowledged, and systemic therapies, radiotherapy, or allogeneic hematopoietic stem cell transplantation (allo-HSCT) should be considered. In the present review, we discuss recent information on MS, focusing on diagnosis, molecular findings, and treatments also considering targetable mutations by recently approved AML drugs.

Clinicopathological characteristics, genetics and prognosis of patients with myeloid sarcoma: a single-center study

AIM

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.

Myeloid Sarcoma: A Primer for Radiologists

ABSTRACT

Myeloid sarcoma (MS) is a rare extramedullary neoplasm that can present in association with acute myeloid leukemia, most commonly in children younger than 15 years. This unique extramedullary malignancy may involve a variety of different organ systems and can present following, preceding, simultaneous with, or in insolation to acute myeloid leukemia. Common areas of extramedullary involvement include soft tissues, bones, lymph nodes, and the peritoneum. Imaging plays a critical role in the diagnosis and management of MS, with commonly used modalities including positron emission tomography-computed tomography, magnetic resonance imaging, computerized tomography, and ultrasound. The purpose of this review article is to provide radiologists with a comprehensive guide summarizing the relevant imaging and clinical features of MS, with emphasis on the role of imaging in the diagnosis, treatment, and follow-up of patients with MS. The relevant pathophysiology, epidemiology, clinical presentations, and differential diagnosis of MS will be reviewed. The relevance of different imaging modalities in diagnosis, monitoring of treatment response, and assessment of treatment-related complications will also be outlined. Through summarizing these topics, this review article aims to provide radiologists with a guide for understanding the existing knowledge of MS in the literature and the current role of imaging in the management of this unique malignancy.

C1Q labels a highly aggressive macrophage-like leukemia population indicating extramedullary infiltration and relapse

Extramedullary infiltration (EMI) is a concomitant manifestation that may indicate poor outcome of acute myeloid leukemia (AML). The underlying mechanism remains poorly understood and therapeutic options are limited. Here, we employed single-cell RNA sequencing on bone marrow (BM) and EMI samples from a patient with AML presenting pervasive leukemia cutis. A complement C1Q+ macrophage-like leukemia subset, which was enriched within cutis and existed in BM before EMI manifestations, was identified and further verified in multiple patients with AML. Genomic and transcriptional profiling disclosed mutation and gene expression signatures of patients with EMI that expressed high levels of C1Q. RNA sequencing and quantitative proteomic analysis revealed expression dynamics of C1Q from primary to relapse. Univariate and multivariate analysis demonstrated adverse prognosis significance of C1Q expression. Mechanistically, C1Q expression, which was modulated by transcription factor MAF BZIP transcription factor B, endowed leukemia cells with tissue infiltration ability, which could establish prominent cutaneous or gastrointestinal EMI nodules in patient-derived xenograft and cell line-derived xenograft models. Fibroblasts attracted migration of the C1Q+ leukemia cells through C1Q-globular C1Q receptor recognition and subsequent stimulation of transforming growth factor β1. This cell-to-cell communication also contributed to survival of C1Q+ leukemia cells under chemotherapy stress. Thus, C1Q served as a marker for AML with adverse prognosis, orchestrating cancer infiltration pathways through communicating with fibroblasts and represents a compelling therapeutic target for EMI.

Breast manifestation of extramedullary myeloid sarcoma: A case report

Extramedullary myeloid sarcoma (MS) of the breast is a rare disease, representing 0.12% of all diagnoses of acute myeloid leukemia. We review a case of a 27-year-old female who presented with a palpable right breast mass. She subsequently underwent a biopsy, which showed breast tissue with diffuse infiltrate of blasts compatible with MS. A bone marrow biopsy was performed with no evidence of leukemia or lymphoma. Therefore, a second breast biopsy was obtained for additional testing and cytogenetics which demonstrated positive (t8;21)(q22;q22) translocation associated with acute myeloid leukemia. Patient was admitted for induction of chemotherapy, but she subsequently developed neutropenic colitis and C. diff colitis. Unfortunately, her condition quickly deteriorated, and she passed away shortly after. This report aims to describe the clinical, radiographic, and pathological features of a case of extramedullary MS involving the breast.

Role of radiotherapy in treatment of extramedullary relapse following total marrow and lymphoid irradiation in high-risk and/or relapsed/refractory acute leukemia

BACKGROUND

Total Marrow and Lymphoid Irradiation (TMLI) is a promising component of the preparative regimen for hematopoietic cell transplantation in patients with high-risk acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL). Extramedullary (EM) relapse after TMLI is comparable to TBI and non-TBI conditioning regimens. This study evaluates outcomes of patients treated with radiotherapy (RT) with EM relapse previously treated with TMLI.

METHODS

A retrospective analysis of five prospective TMLI trials was performed. TMLI targeted bones and major lymphoid tissues using image-guided tomotherapy, with total dose ranging from 12 to 20 Gy. EM recurrences were treated at the discretion of the hematologist and radiation oncologist using RT ± chemotherapy. Descriptive statistics and survival analysis were then performed on this cohort.

RESULTS

In total, 254 patients with refractory or relapsed AML or ALL were treated with TMLI at our institution. Twenty-one patients were identified as receiving at least one subsequent course of radiation. A total of 67 relapse sites (median=2 sites/patient, range=1-16) were treated. Eleven relapsed patients were initially treated with curative intent. Following the initial course of subsequent RT, 1-year, 3-year and 5-year estimates of OS were 47.6%, 32.7% and 16.3%, respectively. OS was significantly better in patients treated with curative intent, with median OS of 50.7 months vs 1.6 months (p<0.001). 1-year, 3-year and 5-year estimates of PFS were 23.8%, 14.3% and 14.3%, respectively. PFS was significantly better in patients treated with curative intent, with median PFS of 6.6 months vs 1.3 months (p<0.001). Following RT, 86.6% of the sites had durable local control.

CONCLUSIONS

RT is an effective modality to treat EM relapse in patients with acute leukemia who relapse after HCT achieving high levels of local control. In patients with limited relapse amenable to curative intent, radiation confers favorable long-term survival. Radiation as salvage treatment for EM relapse after HCT warrants further evaluation.

Presentation of Chloromas in B-Mode Ultrasound and Contrast-Enhanced Ultrasound

Chloromas, also referred to as myeloid sarcomas, describe rare extramedullary tumor aggregates of malignant myeloid progenitor cells. The aim of this study was investigate the diagnostic features and characteristics of chloromas using contrast-enhanced ultrasound (CEUS). Between July 2007 and April 2021, 15 patients with 20 myeloid neoplasms and suspected chloroma manifestations were examined using B-mode US (B-US) and CEUS. Clinical data and B-US (echogenicity, border, size) and CEUS (hyper-, iso-, hypo- or complex enhancement) characteristics were retrospectively analyzed. Absolute and relative frequencies were determined. In B-US, the chloromas were most frequently hypo-echoic (n = 15, 75%). In addition, a hyperechoic (n = 2, 10%) or echocomplex (n = 3, 15%) presentation was observed. On CEUS, 7 chloromas (35%) had an arterial hyperenhancement, 8 (40%) an iso-enhancement and 3 (15%) a complex enhancement. Two chloromas (10%) did not exhibit any enhancement. We describe for the first time CEUS and B-US patterns of chloromas. They are typically hypo-echoic on B-US and have a strong iso- or hyperenhancement on CEUS, which may help in the differential diagnosis of some unclear masses (e.g., hematoma, abscess) in patients with myeloid neoplasias. Nevertheless, histology is necessary for a reliable diagnosis.

The transformation of isolated gastric myeloid sarcoma into acute myeloid leukemia presenting with a complex karyotype and TLS-ERG gene fusion: A case report

RATIONALE

Isolated myeloid sarcoma (MS) is characterized by the rapid proliferation of myeloblasts of acute myeloid leukemia (AML), without any blood or bone marrow involvement. This disease can manifest with extramedullary organ involvement, such as the skin, lymph nodes, bone, brain, breast cervix, and visceral organs, while the occurrence of myeloid sarcomas in the stomach is rare. Isolated MS has been associated with acute myeloid leukemia (AML), but the rapid progression of MS to acute myeloid leukemia with a complex karyotype and TLS-ERG fusion gene is even rarer.

PATIENT CONCERNS

A 33-year-old woman suffered from persistent epigastric pain accompanied by two months of anorexia and nausea, as well as 1-week of melena.

DIAGNOSIS

This patient was initially diagnosed with gastric MS that eventually transformed into AML with a complex karyotype and TLS-ERG fusion gene, 4 months later.

INTERVENTIONS

Only palliative care, including nutrition support, antacids, blood transfusion, anti-infection methods were used on this patient to determine the cachexia status and the family's requirement.

OUTCOMES

Routine follow-up results demonstrated this patient had died due to cerebral hemorrhage five months after the diagnosis of MS.

LESSONS

Comprehensive integration of patient history, imaging features, mass and bone marrow biopsy, and molecular cytogenetic may provide insights that could help us avoid the misdiagnosis of gastric MS. Isolated gastric MS can rapidly progress to AML with a poor prognosis if the patient does not receive appropriate treatment.

Molecular profiling and clinical implications of patients with acute myeloid leukemia and extramedullary manifestations

Background

Extramedullary manifestations (EM) are rare in acute myeloid leukemia (AML) and their impact on clinical outcomes is controversially discussed.

Methods

We retrospectively analyzed a large multi-center cohort of 1583 newly diagnosed AML patients, of whom 225 (14.21%) had EM.

Results

AML patients with EM presented with significantly higher counts of white blood cells (p < 0.0001), peripheral blood blasts (p < 0.0001), bone marrow blasts (p = 0.019), and LDH (p < 0.0001). Regarding molecular genetics, EM AML was associated with mutations of NPM1 (OR: 1.66, p < 0.001), FLT3-ITD (OR: 1.72, p < 0.001) and PTPN11 (OR: 2.46, p < 0.001). With regard to clinical outcomes, EM AML patients were less likely to achieve complete remissions (OR: 0.62, p = 0.004), and had a higher early death rate (OR: 2.23, p = 0.003). Multivariable analysis revealed EM as an independent risk factor for reduced overall survival (hazard ratio [HR]: 1.43, p < 0.001), however, for patients who received allogeneic hematopoietic cell transplantation (HCT) survival did not differ. For patients bearing EM AML, multivariable analysis unveiled mutated TP53 and IKZF1 as independent risk factors for reduced event-free (HR: 4.45, p < 0.001, and HR: 2.05, p = 0.044, respectively) and overall survival (HR: 2.48, p = 0.026, and HR: 2.63, p = 0.008, respectively).

Conclusion

Our analysis represents one of the largest cohorts of EM AML and establishes key molecular markers linked to EM, providing new evidence that EM is associated with adverse risk in AML and may warrant allogeneic HCT in eligible patients with EM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-022-01267-7.

Neoplastic nerve lesions

Though metastasis and malignant infiltration of the peripheral nervous system is relatively rare, physicians should have a familiarity with their presentations to allow for prompt diagnosis and initiation of treatment. This article will review the clinical presentations, diagnostic evaluation, and treatment of neoplastic involvement of the cranial nerves, nerve roots, peripheral nerves, and muscle. Due to the proximity of the neural structure traversing the skull base, metastasis to this region results in distinctive syndromes, most often associated with breast, lung, and prostate cancer. Metastatic involvement of the nerve roots is uncommon, apart from leptomeningeal carcinomatosis and bony metastasis with resultant nerve root damage, and is characterized by significant pain, weakness, and numbness of an extremity. Neoplasms may metastasize or infiltrate the brachial and lumbosacral plexuses resulting in progressive and painful sensory and motor deficits. Differentiating neoplastic involvement from radiation-induced injury is of paramount importance as it dictates treatment and prognosis. Neurolymphomatosis, due to malignant lymphocytic infiltration of the cranial nerves, nerve roots, plexuses, and peripheral nerves, deserves special attention given its myriad presentations, often mimicking acquired demyelinating neuropathies.

Gastric Myeloid Sarcoma Mimicking a Scirrhous Gastric Cancer

Myeloid sarcoma (MS) is a relatively rare manifestation of myeloid neoplasms at sites other than the bone marrow. The rarity of gastrointestinal (GI) MS is attributed to certain factors, such as misdetection due to insufficient endoscopic assessments at the initial presentation with acute myeloid leukemia (AML) as well as the difficulty of making a histologic assessment of leukemic involvement of the GI tract. We herein report a case of AML with gastric involvement and discuss the importance of screening examinations and therapies considering the location of MS and the data of cytogenetic and molecular mutation.

Testicular myeloid sarcoma: a relapse of acute myeloid leukaemia after allogeneic peripheral blood stem cell transplantation- a rare presentation

Myeloid sarcoma is an uncommon pathological diagnosis of proliferation of blasts of one or more of the myeloid lineages in regions other than the blood and bone marrow. Myeloid sarcoma of the testis after allogeneic bone marrow stem cell transplantation is very rare and only few cases are reported in the literature. It is usually misdiagnosed as malignant lymphoma, particularly with large cell lymphoma, due to similar histological morphology. Due to difficulty in diagnosis, it is suggested that an appropriate panel of immunohistochemical marker studies be performed in conjunction with clinical correlation to avoid misleading diagnosis and improper treatment of patients. We report an interesting case of a 49-year-old man with a diagnosis of acute myelogenous leukaemia. He had undergone allogeneic peripheral blood stem cell transplantation, achieved complete molecular remission and later relapsed with myeloid sarcoma of the testis.

Widespread myeloid sarcoma with KMT2A rearrangement involving the testis, oral cavity, heart, kidney and gallbladder without bone marrow involvement

Myeloid sarcoma is a solid hematological tumor consisting of growing immature myeloid cells in tissues outside the bone marrow. Myeloid sarcoma presenting before the onset of bone marrow disease is rare. Here, we report the case of a young 35-year-old male who presented with testicular mass and was diagnosed with widespread myeloid sarcoma involving internal organs like heart, kidney and gallbladder. Peripheral blood and bone marrow examination did not show any evidence of leukemia. Genetic analysis was significant for KRAS G12D mutation and KMT2A rearrangement. Induction chemotherapy for extramedullary AML with cladribine, cytarabine, GM-CSF and idarubicin (CLAG-IDA) achieved complete remission. However, the patient relapsed after 2 months and developed rapidly progressive disease. The disseminated nature of the disease in a patient without bone marrow involvement are what make this case extremely rare. Involvement of organs like heart, gall bladder and kidney is also uncommon. Isolated myeloid sarcoma is a challenge to diagnose as there are no manifestations of leukemia in peripheral blood or bone marrow, so it is usually not considered among the differential diagnoses. KM2TA rearrangement identified on genetic analysis is a rare finding in patients with AML and is associated with poor outcomes. KRAS mutations are currently being studied as therapeutic targets in these patients. This case report describes the detailed diagnostic process and discusses the possible strategies for diagnosis and treatment that can be used in similar cases.

The Bone Marrow Microenvironment Mechanisms in Acute Myeloid Leukemia

Bone marrow (BM) is a highly complex tissue that provides important regulatory signals to orchestrate hematopoiesis. Resident and transient cells occupy and interact with some well characterized niches to produce molecular and cellular mechanisms that interfere with differentiation, migration, survival, and proliferation in this microenvironment. The acute myeloid leukemia (AML), the most common and severe hematological neoplasm in adults, arises and develop in the BM. The osteoblastic, vascular, and reticular niches provide surface co-receptors, soluble factors, cytokines, and chemokines that mediate important functions on hematopoietic cells and leukemic blasts. There are some evidences of how AML modify the architecture and function of these three BM niches, but it has been still unclear how essential those modifications are to maintain AML development. Basic studies and clinical trials have been suggesting that disturbing specific cells and molecules into the BM niches might be able to impair leukemia competencies. Either through niche-specific molecule inhibition alone or in combination with more traditional drugs, the bone marrow microenvironment is currently considered the potential target for new strategies to treat AML patients. This review describes the cellular and molecular constitution of the BM niches under healthy and AML conditions, presenting this anatomical compartment by a new perspective: as a prospective target for current and next generation therapies.

CNS involvement in AML at diagnosis is rare and does not affect response or survival: data from 11 ECOG-ACRIN trials

There was no significant difference in CR rate and OS among patients with CNS involvement, other EMD, or no EMD.

The incidence of CNS involvement of newly diagnosed AML is low, irrespective of whether an LP is mandatory or not.

Central nervous system (CNS) involvement in patients with newly diagnosed acute myeloid leukemia (AML) is rare, and systematic data regarding outcome are scarce. This retrospective study summarized data from 11 consecutive Eastern Cooperative Oncology Group-American College of Radiology Imaging Network (ECOG-ACRIN) clinical trials for patients with newly diagnosed AML. In all, 3240 patients with AML were analyzed, and 36 (1.11%) were found to have CNS involvement at diagnosis. The incidence of CNS disease among the 5 studies with per protocol mandatory lumbar puncture (LP) was similar to the incidence among studies in which LP was performed at the discretion of the investigator (0.86% vs 1.41%; P = .18). There was no significant difference in the rate of complete remission (CR) among patients with CNS involvement and those with other extramedullary disease (EMD) sites or those with no EMD (52.8% vs 59.3%-60%). The median overall survival (OS) for patients who were CNS positive, who had other EMD, or who had no EMD was 11.4, 11.3, and 12.7 months, respectively. There was no difference in OS among patients with CNS involvement, those with other EMD (hazard ratio [HR], 0.96; adjusted P = .84), and those with no EMD (HR, 1.19; adjusted P = .44). In conclusion, the reported incidence of CNS involvement in patients with newly diagnosed AML is low (1.1%), irrespective of whether an LP is mandatory or not. The presence of CNS disease at diagnosis in and of itself does not seem to portend a poor prognosis for achieving an initial CR or for OS.

Gastrointestinal Myeloid Sarcoma a Case Presentation and Review of the Literature

Myeloid sarcomas can be detected in up to 30% of acute myeloid leukemia cases or occur de-novo without bone marrow involvement. The most frequent localization of myeloid sarcomas in the abdominal cavity is the small intestine, and gastric presentations are infrequent, frequently misdiagnosed, and a high level of suspicion should exist when the characteristic histomorphology features are present. The current review features a case report with gastric presentation of myeloid sarcoma in a patient with a diagnosis of acute myeloid leukemia with trisomy 8. In addition, a review of the literature of intestinal-type myeloid sarcomas shows that less than 15% of these cases have been reported in the stomach. The most common molecular aberrancy detected in intestinal myeloid sarcomas is the fusion protein CBFB-MYH11. A review of several large studies demonstrates that the presence of myeloid sarcoma does not constitute an independent prognostic factor. The therapeutic approach will be tailored to the specific genetic abnormalities present, and systemic chemotherapy with hematopoietic stem cell transplant is the most efficient strategy.

Chloroma of the Bladder: A Case Report of Leukemia Progression Presenting as Hematuria

Myeloid sarcoma (MS) is a rare extramedullary manifestation of acute myelogenous leukemia (AML). The mass is composed of primitive myeloid cells that can occur in a variety of organs, most commonly the skin, lymph nodes, GI tract, bone, breast, and CNS. Involvement of the genitourinary tract is rare. Consensus on treatment of MS has not been established, but management typically involves systemic therapy, such as chemotherapy or allogeneic hematopoietic stem cell transplant as well as palliative local therapies such as radiation or surgery. Outcomes of MS using novel AML therapies, such as BCL-2 inhibitors or IDH inhibitors, remain undescribed. We describe a rare case of a 70-year-old man presenting with MS of the urinary bladder complicating known secondary AML (RUNX1 and IDH2 mutated). Prior to development of bladder MS, the patient had received decitabine, enasidenib, and venetoclax. Following diagnosis, he was treated with cytarabine and venetoclax. To our knowledge, this is the first case of bladder MS treated with a BCL-2 inhibitor.

Myeloid sarcoma as a manifestation of acute myeloid leukemia

We report a case of a 43-year-old man who presented with dyspnea because of large bilateral pleural effusions and imaging findings of a large periaortic mass with compression of the esophagus and left atrium. Subsequent soft tissue biopsy was consistent with myeloid sarcoma, and bone marrow biopsy was consistent with acute myeloid leukemia. He was started on induction and subsequent consolidation chemotherapy with complete remission and shrinkage of the tumor.

De Novo Granulocytic Sarcoma of the Humerus in an 82-Year-Old Woman: A Case Report

Granulocytic sarcoma is a rare solid malignant tumor that occurs in patients with acute myeloid leukemia. As such, granulocytic sarcoma without leukemia occurring in long bones is quite rare. This case report describes an isolated granulocytic sarcoma of the right humerus in an 82-year-old woman in the absence of acute myeloid leukemia. The patient was admitted to our hospital with a pathological fracture of the right humerus. An incisional biopsy was performed, and the pathological diagnosis was granulocytic sarcoma. Radiotherapy (45 Gy) to the humerus resulted in a good clinical outcome with no evidence of myeloid leukemia at 9.5 years of follow-up. Radiotherapy was effective for pain relief and maintenance of good quality of life in this patient. Although laboratory evaluation has not revealed any abnormalities 9.5 years after radiotherapy, periodic observation is required.

Multiple primary tumor of hematopoietic tissue: myeloid sarcoma in combination with mantle cell lymphoma. Case report

The prevalence of multiple primary tumors has significantly increased last time. The question of choosing the optimal tactics of therapy today not fully resolved. Particular interest is the simultaneous detection of two neoplasms of similar origin in one study biopsy material. This publication presents a case of simultaneous diagnosis of myeloid sarcoma and mantle cell lymphoma in a 65-year-old patient, which required use of two different chemotherapy protocols. This example shows the need to use an extended diagnostic approach at all stages of the therapy, which allows choosing right tactics of therapy and achieving complete remission of two neoplasms.

A Journey Across Oceans With a Heavy Heart: Rare Presentation of a Pediatric Malignancy

Myeloid sarcoma, due to extramedullary deposition of myeloblasts, is one of the rare presentations in acute myeloid leukemia. We present an extremely rare case of a 5-year-old boy with cardiac myeloid sarcoma. Noninvasive mode of diagnosis, timely initiation of chemotherapy and meticulous supportive care are the keys to successful outcome. (Level of Difficulty: Intermediate.)

Leukaemia cutis for clinicians, a literature review

Leukaemia cutis (LC) describes infiltration of the skin by leukaemia cells, resulting in clinically identifiable cutaneous lesions. LC has a wide range of clinical manifestations, which can make it difficult to distinguish LC from other skin changes. In a group of patients, LC can be the first manifestation of leukaemia, therefore skin biopsy is crucial for the diagnosis. In this mini review, we discuss various types of leukaemia most frequently represented in leukaemia cutis, in both children and adults and skin changes in multiple myeloma, focusing on the clinical presentation of LC and prognosis in patients.

Oral myeloid sarcoma as an uncommon manifestation of acute myeloid leukemia: A case series and review of the literature

BACKGROUND AND OVERVIEW

Oral myeloid sarcoma (MS) is an extramedullary tumor that can occur in the setting of acute myeloid leukemia, either as the first sign of an underlying disease or later in the course of disease. The authors' aim was to present the clinical features of oral MS and review the literature.

CASE DESCRIPTION

Case 1 was an 82-year-old woman with an asymptomatic erythematous swelling on the maxillary gingiva and no history of hematologic malignancy. Case 2, a 65-year-old man, and case 3, a 58-year-old woman, each had a history of acute myeloid leukemia and a painful ulcer on the palatal mucosa and an asymptomatic ulcer on the lower lip mucosa, respectively. Case 1 was treated with focal radiation then chemotherapy and achieved complete remission initially, but died of relapse 2 years after diagnosis. Case 2 received radiotherapy and immunotherapy and had a complete response. Case 3 received chemotherapy and achieved remission initially, but relapsed and is undergoing investigational targeted therapies.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

Oral MS can manifest as gingival or mucosal swelling or ulceration and can indicate onset or relapse of associated hematologic malignancies, which often have a poor prognosis. Because patients with oral findings are likely to seek treatment from their dentists first, oral clinicians should maintain a broad differential diagnosis list when evaluating oral lesions, especially if treatment prescribed for a more common diagnosis fails to resolve the lesion.

The myeloid sarcoma treated by Venetoclax with hypomethylating agent followed by stem cell transplantation: rare case report

BACKGROUND

Myeloid sarcoma (MS) is a very rare condition, develops both in patients with other hematological neoplasms, and as isolated tumor. MS of the gynecologic tract is extremely rare. An available literature data about diagnosis and management of MS is summarized in the article. The role of chemotherapy, radiation therapy, surgery and bone marrow transplantation in the treatment is discussed. Polychemotherapy and allogeneic bone marrow transplantation were suggested to be the optimal treatment strategy of MS of the gynecological tract. The use of new targeted agents results in promising clinical data.

CASE PRESENTATION

We are presenting a rare clinical case of a MS of the uterine cervix with concomitant bone marrow involvement and describe all the peculiarities of the clinical course, diagnosis, and treatment. The patient received chemotherapy followed by allogeneic bone marrow transplantation. The pre-transplant therapy allowed us to perform allogeneic bone marrow transplantation with the deepest response possible: complete PET-negative and MRD-negative remission of the disease.

CONCLUSIONS

MS remains a subject of discussion regarding its diagnostic and therapeutic aspects. The use of novel targeting agents can be perspective option for patient with extramedullary disease.

Acute myeloid leukemia with leukemic pleural effusion and high levels of pleural adenosine deaminase: A case report and review of literature

Pleural effusions are rarely observed in association with acute myeloid leukemia (AML), and their true incidence remains unknown. Given the low diagnostic yield from cytopathologic analysis of malignant pleural effusions and the fact that patients with leukemia are often thrombocytopenic and unable to tolerate invasive procedures, the incidence of leukemic effusions may be underestimated. Here, we report a rare case of pleural effusion in a patient with newly diagnosed AML. Initial analysis revealed an exudative, lymphocyte-predominant effusion. High levels of adenosine deaminase (ADA) were detected in pleural fluid, consistent with a diagnosis of tuberculosis. However, the analysis of pleural cytology revealed leukemic cells, permitting the diagnosis of leukemic effusion to be made. The patient underwent induction chemotherapy and pleural effusion resolved without recurrence. This case emphasizes the diagnostic dilemma presented by high levels of ADA in a leukemic pleural effusion, as this association has not been previously considered in the literature.

Brachial plexus chloroma as a presenting feature of relapse in a child with KMT2A-rearranged acute lymphoblastic leukemia, a case report

Approximately 30–40% of relapses in pediatric acute lymphoblastic leukemia (ALL) are extra-medullary. KMT2A gene rearrangements are common in patients with infantile ALL. Chloromas are rare tumors composed of collections of acute leukemic cells that typically involve the bone or skin. Exceptionally uncommon, chloromas invade the peripheral nervous system, a phenomenon termed “neuroleukemiosis.” We describe A 6-year-old girl with a history of pre-B ALL with CNS involvement and KMT2A rearrangement diagnosed initially at 4 months of age. During continuation therapy she developed a scalp mass that was confirmed to be a leukemic relapse. She underwent re-induction chemotherapy followed by blinatumomab with subsequent remission and proceeded to allogeneic hematopoietic cell transplant (HCT). Three years following HCT, she presented with brachial plexus palsy and was found to have a lymphoblastic chloroma invading the brachial plexus. Review of existing literature shows relapse in pediatric ALL patients presenting as brachial plexus chloroma has only been documented once before. It has long been suggested that KMT2A gene rearrangements play a role in development of chloromas in patients with AML, however it is still unclear what role KMT2A has in ALL. Here we report a rare case of ALL relapse that presented as a left arm palsy secondary to a leukemic chloroma invading the brachial plexus and aim to explore the potential role of KMT2A in the formation of ALL chloromas.

Case Report: Refusal of an Veno-Arterial Extracorporeal Membrane Oxygenation Due to Malignant Disease? - An Extremely Rare Form of Cardiac Involvement in Acute Myeloid Leukemia

We report here on a 61-year-old patient with acute right heart failure of unclear etiology. Echocardiography revealed a myocardial mass infiltrating the heart, though, we assumed a cardiac lymphoma. A VA-ECMO was implanted as bridging for diagnosis and therapy. Our patient received chemotherapy, under which the tumor (of unknown etiology at this point) reached a partial remission. Nine months after first admission the patient developed acute myeloid leukemia with DNMT3a and TET2 mutations. Retrospective analysis of the cardiac biopsy revealed the identical mutations and matched with the diagnosis of an extremely rare primary extramedullary manifestation of an AML (myelosarcoma). The patient received induction-chemotherapy and was planned for consolidating allogeneic stem cell transplantation. From this case, we conclude that an extracorporeal therapy should be discussed in selected patients even in case of an initially fatal appearing prognosis. In selected cases, extracorporeal support can generate enough time for diagnosis and therapy. However, transparent planning, including discussion of best supportive care strategies involving the patient's family are indispensable requirements for starting ECMO in such patients.

Polyserositis as a primary clinical manifestation of CD7+ acute myelogenous leukemia with myeloid sarcoma: A case report

RATIONALE

Myeloid sarcomas (MS) are defined as rare extramedullary masses composed of immature myeloid cells. MS mostly develops in patients with acute myeloid leukemia (AML), and involves primarily the skin, soft tissues, bones, and lymph nodes. Pleura and pericardium involvement of MS are extremely uncommon. Polyserositis is also a very rare extramedullary presentation of acute myeloid leukemia (AML).

PATIENT CONCERNS

A 30-year-old woman with a complaint of right neck mass combined with coughing for 2 months as well as fever and systemic edema for the last 10 days, was admitted to our center on July 11, 2019. Initial positron emission tomography (PET) scan indicated systemic lymphadenopathy, bilateral pleural effusion, and pericardial effusion.

DIAGNOSIS

The initial pathological diagnosis of lymph nodes was MS. Subsequent bone marrow analysis confirmed AML.

INTERVENTIONS

Conventional IA induction regimen followed by high-dose cytarabine (HiDAC) regimen.

OUTCOMES

Complete absorption of pericardial and pleural effusion after the first cycle of IA induction chemotherapy.

LESSONS

Polyserositis can be an extramedullary presentation of AML. Patients with polyserositis should undergo routine flow cytometric analysis. For AML with extamedullary infiltration, systemic chemotherapy should be administered in all confirmed cases.

Myeloid sarcoma, chloroma, or extramedullary acute myeloid leukemia tumor: A tale of misnomers, controversy and the unresolved

The World Health Organization classification and definition of "myeloid sarcoma" is imprecise and misleading. A more accurate term is "extramedullary acute myeloid leukemia tumor (eAML)." The pathogenesis of eAML has been associated with aberrancy of cellular adhesion molecules, chemokine receptors/ligands and RAS-MAPK/ERK signaling. eAML can present with or without synchronous or metachronous intramedullary acute myeloid leukemia (AML) so a bone marrow evaluation is always recommended. Accurate diagnosis of eAML requires tissue biopsy. eAML confined to one or a few sites is frequently treated with local therapy such as radiotherapy. About 75-90% of patients with isolated eAML will develop metachronous intramedullary AML with a median latency period ranging from 4 to 12 months; thus, patients with isolated eAML may also be treated with systemic anti-leukemia therapy. eAML does not appear to have an independent prognostic impact; selection of post-remission therapy including allogeneic hematopoietic cell transplant (alloHCT) is typically guided by intramedullary disease risk. Management of isolated eAML should be individualized based on patient characteristics as well as eAML location and cytogenetic/molecular features. The role of PET/CT in eAML is also currently being elucidated. Improving outcomes of patients with eAML requires further knowledge of its etiology and mechanism(s) as well as therapeutic approaches beyond conventional chemotherapy, ideally in the context of controlled trials.

Extramedullary Acute Myeloid Leukemia of the Renal Pelvis: Insights into a Visceral Niche

Acute myeloid leukemia (AML) is a stem cell malignancy that originates in the bone marrow and involves the peripheral blood. Extramedullary AML is rarer, but it is most commonly associated with the former French-American-British (FAB) subtypes M4 or M5 of AML. AML cells may also home to the central nervous system and other solid organs such as cortical bone and skin. Such target sites of metastasis depend on microenvironmental niche interactions, which have not been fully elucidated to date. Visceral organs usually do not represent a favorable niche for AML stem cell occupancy. Herein, we describe the case of an 80-year-old man with extramedullary AML involvement of the renal pelvis. Hypercalcemia and obstructive uropathy were presenting features. The visceral niche is a rare site of involvement of myeloid malignancy, and hypercalcemia may reflect a mechanism of extramedullary involvement. We propose a treatment paradigm for this uncommon subset of AML based on advanced age and complex karyotype.

Differential Localization and Invasion of Tumor Cells in Mouse Models of Human and Murine Leukemias

Leukemias are refractory hematopoietic malignancies, for which the development of new therapeutic agents requires in vivo studies using tumor-bearing mouse models. Although several organs are commonly examined in such studies to evaluate the disease course, the effectiveness of interventions and the localization of tumor cells in the affected organs are still unclear. In this study, we histologically examined the distribution of leukemia cells in several organs using two leukemic mouse models produced by the administration of two cell lines (THP-1, a human myelomonocytic leukemia, and A20, a mouse B cell leukemia/lymphoma) to severe immunodeficient mice. Survival of the mice depended on the tumor burden. Although A20 and THP-1 tumor cells massively infiltrated the parenchyma of the liver and spleen at 21 days after transplantation, A20 cells were hardly found in connective tissues in Glisson’s capsule in the liver as compared with THP-1 cells. In the bone marrow, there was more severe infiltration of A20 cells than THP-1 cells. THP-1 and A20 cells were widely spread in the lungs, but were rarely observed in the small intestine. These findings suggest that each leukemia model has a unique localization of tumor cells in several affected organs, which could critically affect the disease course and the efficacy of therapeutic agents, including cellular immunotherapies.

Diagnostic and Therapeutic Considerations for Extramedullary Leukemia

PURPOSE OF REVIEW

The purpose of this review is to summarize the current literature on the presentation, diagnosis, and treatment options available for extramedullary (EM) manifestations of leukemia including myeloid sarcoma (MS) and leukemia cutis (LC).

RECENT FINDINGS

Advanced imaging using 18FDG-PET/CT is an effective screening tool for EM manifestations of leukemia. The role of radiation therapy has been more clearly delineated in the treatment of both MS and LC. FDA-approved targeted agents have improved outcomes in patients with AML but have not demonstrated improvements specifically for EM; however, a checkpoint inhibitor, Ipilimumab, holds promise in impacting local control for the treatment of AML-related EM. EM manifestations of leukemia pose significant therapeutic challenges. Treatment of EM is predicated on multiple factors including the presence of concomitant bone marrow involvement, AML-risk classification, and timing of presentation at initial diagnosis or relapse following systemic therapy.

Aleukemia cutis: Clinicopathological and molecular investigation of two cases

We describe two cases of acute myeloid leukemia (AML) who presented with cutaneous manifestations. Leukemia cutis (LC) is the cutaneous presentation of any type of leukemia and occurs in 10% to 15% of patients with AML, but cutaneous infiltration of AML rarely precedes the involvement of the bone marrow or peripheral blood and is called "aleukemia cutis." Our first case presented with facial skin thickening, a manifestation which is known as lionization and his initial clinical diagnosis was nonspecific allergic reaction. Our second case presented with urticaria-like lesions with the initial clinical and histomorphologic diagnoses of leukocytoclastic vasculitis. Histopathologic examination of skin biopsy specimens in both patients showed diffuse infiltration of the dermis with a monotonous population of intermediate-sized mononuclear cells by open chromatin and promonocytic features. Bone marrow aspiration leukocyte karyotyping showed normal cytogenetics, and molecular investigation revealed mutations of NPM1 and FLT3 genes. Somatic CEBPA gene mutation was negative in both patients. LC as the first manifestation of leukemia is very rare and could result in delayed diagnosis and affect patient prognosis.