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Introduction to Myeloproliferative Neoplasms
Published in Wojciech Gorczyca, Atlas of Differential Diagnosis in Neoplastic Hematopathology, 2014
CML is characterized by marked leukocytosis (often >100 × 109/L) with neutrophils at various stages of maturation, mostly segmented forms, and myelocytes, accompanied by eosinophils and basophils. CNL also shows neutrophilia, but there is predominance of segmented forms with occasional bands. The neutrophils of CNL show prominent cytoplasmic granules. Leukocytosis with predominance of eosinophils is characteristic for CEL/HES. Neutrophilia and basophilia often present in PV, but it is not as pronounced as in CML. Mild leukocytosis may also be present in early PMF. Anemia and leukoerythroblastosis are seen typically in fibrotic stage of PMF. ET shows marked thrombocytosis, but normal WBC count or only mild leukocytosis. The differential diagnosis also includes other disorders associated with increased WBC count, B and T lymphoproliferations, CMML, reactive monocytosis, acute monoblastic leukemia, B- and T-ALL, AML as well as reactive processes (leukemoid reaction). Leukemoid reaction is defined as a persistent, reactive neutrophilic leukocytosis >50 × 109/L in response to infection, inflammation, or therapeutic agents such as growth factors and malignancy (there is no associated leukemia). The major causes of leukemoid reactions are severe infections, intoxications, malignancies, severe hemorrhage, or acute hemolysis [85]. A significant increase in the WBC in patients with malignancy (paraneoplastic leukemoid reaction) is often due to production of CSFs (e.g., G-CSF) by tumor cells. Lymphomas (with or without blood involvement) may also present with leukemoid reaction. Promyelocytic leukemoid reaction may accompany mycobacterial infections.
Benign Disorders of Leukocytes
Published in Harold R. Schumacher, William A. Rock, Sanford A. Stass, Handbook of Hematologic Pathology, 2019
Gene L. Gulati, Zoran Gatalica, Bong H. Hyun
A leukemoid reaction is characterized by either (a) leukocytosis of 50.0 × 109/L or higher with a shift to the left, or (b) the presence of a considerable number of immature cells (metamyelocytes, myelocytes, promyelocytes, and even an occasional blast cell) in the peripheral blood, mimicking leukemia (Fig. 2). In the latter case, the WBC count may be above normal, normal, or rarely below normal. Depending on the predominant cell type, the leukemoid reaction may be neutrophilic, eosinophilic, or lymphocytic. Monocytic and basophilic leukemoid reactions, if they occur, are rare. Among the various types of leukemoid reactions, neutrophilic is the one most frequently encountered in clinical practice. In fact, it is so common that the term leukemoid reaction is presumed to refer to neutrophilic reaction unless specified otherwise. Neutrophilic leukemoid reaction may occur in many of the conditions associated with neutrophilia (Table 2). Cytoplasmic changes, such as toxic granulation, vacuolization, and Döhle bodies, along with a high neutrophil alkaline phosphatase (NAP) score, help to differentiate the leukemoid reaction from chronic myelogenous leukemia (CML), which is generally characterized by a large proportion of myelocytes, eosinophilia, basophilia, and a low NAP score. The diagnosis of CML is confirmed by the presence of Philadelphia chromosome or BCR-ABL gene rearrangement, both of which are absent in the leukemoid reaction. The leukemic hiatus, a characteristic of acute leukemia, is also absent in the leukemoid reaction. Eosinophilic leukemoid reactions usually occur in children and are generally caused by parasitic infections. Lymphocytic leukemoid reactions may occur in whooping cough, infectious lymphocytosis, infectious mononucleosis, and tuberculosis.
Case Report of Acute Splenic Sequestration Crisis in an Adult Patient with Hb S Disease and Suspected Hereditary Persistence of Fetal Hemoglobin
Published in Hemoglobin, 2021
Ian R. Sigal, Christine A. Ciunci
Acute splenic sequestration crisis is a rare complication of sickle cell disease in adults that typically presents with splenic enlargement, abdominal pain, and an acute drop in Hb. Acute splenic sequestration crisis most commonly occurs in adult patients with heterozygous sickle cell disease, although ASSC has been reported in patients with homozygous Hb S disease as well. This case demonstrates ASSC in a patient with homozygous Hb S disease who remained at-risk due to an abnormally high Hb F fraction. Furthermore, this case highlights that leukemoid reaction can be a feature of ASSC and does not necessarily represent severe infection. Due to significant mortality in patients with unrecognized ASSC, providers should consider this condition when caring for sickle cell disease patients with acute abdominal pain.
Melanoma induced immunosuppression is mediated by hematopoietic dysregulation
Published in OncoImmunology, 2018
Neha Kamran, Youping Li, Maria Sierra, Mahmoud S. Alghamri, Padma Kadiyala, Henry D. Appelman, Marta Edwards, Pedro R. Lowenstein, Maria G. Castro
Based on our findings we propose a model where melanoma growth either directly through IL-3 or other tumor derived PAMPs and TLR ligands induces hematopoietic skewing to myelopoiesis (Supplementary figure 9). Tumor growth mimics chronic inflammation and triggers BM mobilization and activation of extramedullary hematopoiesis to meet the demands of myeloid cell production. Tumor derived factors or host factors activated in response to tumor growth also impact erythropoiesis and lymphopoiesis thus creating an environment amenable to tumor progression. Leukemoid reaction has been described in a variety of solid tumors such as bladder carcinoma, sarcoma, lung cancer and cervical cancer.2,35-38 Wen-Chao Wu et al. demonstrated a 4–7 fold increase in circulating hematopoietic stem and progenitor cells such as GMPs in the peripheral blood of 90 patients with solid tumors.39 Importantly, they also found that the frequency of these circulating GMPs correlated with tumor progression.39 Paraneoplastic syndrome with granulocytosis was observed in 6 patients with metastatic melanoma.40 Infection, bone marrow metastasis and corticosteroid therapy were ruled out as the underlying mechanisms and high levels of serum GCSF in these patients were found to directly correlate with the elevated WBC counts. The metastatic melanoma was believed to be the source of the ectopic GCSF.40 Two other studies have also identified leukocytosis in melanoma patients with elevated GCSF production by the melanoma tumor and increased serum levels.41,42 Another recent case report also showed leukocytosis in a stage IIIA malignant melanoma patient with a BRAF V600E mutation.43 Interestingly, GCSF in combination with Fms like tyrosine kinase 3 ligand (Flt3L) and GMCSF can lead to the expansion of myeloid progenitors in the context of mammary tumors.44 The observed hematopoietic changes observed in this study with mammary tumors were associated with altered histone methylation in the myeloid progenitors.44 Elevated neutrophil and leukocyte counts in melanoma patients have been found to be associated with poor overall survival and reduced progression free survival by multiple studies.45 Moreover, a study in 1983 also showed that patients with normal lymphocyte counts had a better prognosis than patients with lymphopenia and a positive correlation between lymphocyte counts and treatment response has been also observed.45,46 Thus it is apparent that identification of factors resulting in this paraneoplastic syndrome is crucial for development of anti-melanoma therapies with enhanced efficacy. Understanding the mechanism regulating this tumor-induced paraneoplastic syndrome will also aid in predicting patient responses to anti-tumor therapies and impact survival.