POEMS syndrome is a life-threatening syndrome due to an underlying plasma cell neoplasm. The major criteria for the syndrome are polyneuropathy, clonal plasma cell disorder (PCD), sclerotic bone lesions, elevated vascular endothelial growth factor, and the presence of Castleman disease. Minor features include organomegaly, endocrinopathy, characteristic skin changes, papilledema, extravascular volume overload, and thrombocytosis.

Essential thrombocythemia (ET) is a classic Philadelphia chromosome-negative myeloproliferative neoplasm characterized by excessive proliferation of bone marrow megakaryocytes and sustained elevation of peripheral blood platelet counts. The primary clinical risks include thrombotic and bleeding events, with a minority of patients experiencing the risk of progression to myelofibrosis or transformation to acute leukemia. In recent years, the demand for standardized diagnosis and treatment of ET has become increasingly prominent with advances in molecular testing, bone marrow pathology diagnosis, novel drug development, and clinical management. To provide actionable clinical practice guidance for hematologists in China, the Thrombosis and Hemostasis Group of the Chinese Society of Hematology, Chinese Medical Association, convened domestic experts to formulate this guideline, based on both international and domestic evidence-based medical evidence combined with expert consensus.

POEMS syndrome is a rare multisystem disorder caused by a monoclonal plasma cell neoplasm, characterized by polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes. Due to its overlapping features with other neuropathies, diagnosis is often delayed, impacting prognosis. We report a 37-year-old male presenting with progressive limb weakness, inguinal lymphadenopathy, and spinal nerve root enhancement. Imaging revealed mixed lytic-sclerotic bony lesions, lymphadenopathies, hepatosplenomegaly, and spinal nerve root thickening and enhancement, which raised early suspicion for an underlying plasma cell dyscrasia rather than an isolated inflammatory neuropathy. Electrodiagnostic studies showed subacute demyelinating polyradiculoneuropathy with axonal degeneration, and laboratory findings included hypoalbuminemia, anemia, and thrombocytosis. A biopsy from the lymphadenopathy confirmed mixed plasma cell and hyaline vascular type Castleman disease, establishing POEMS syndrome in the context of a systemic plasma cell disorder. This case highlights how characteristic combinations of nerve root enhancement and mixed lytic-sclerotic bone lesions on MRI and CT can contribute uniquely to early diagnosis and differentiation from mimics such as chronic inflammatory demyelinating polyradiculoneuropathy or leptomeningeal disease, enabling prompt initiation of clone-directed therapy. Increased awareness of these imaging patterns among clinicians is critical for timely diagnosis and management.

Polycythaemia vera (PV) is a chronic myeloproliferative neoplasm characterised by proliferation of erythroid lineages leading to erythrocytosis and can also present with variable proliferation of myeloid and megakaryocytic lineages causing leukocytosis and thrombocytosis. PV is strongly associated with mutations in the JAK2 gene with the mutation being found in >95% of patients with PV. It can present with splenomegaly, which tends to cause abdominal pain. Diagnosis is based on the WHO criteria, which is based on haemoglobin and haematocrit levels, the presence of JAK2 mutations and erythropoietin levels with bone marrow changes. Typically, PV is managed with low-dose aspirin to prevent thrombotic complications, venesection to control haematocrit and cytoreductive therapy. This case discusses an unusual presentation of a patient with polycythaemia vera who presented with chest pain, leading to delays in diagnosis.

Mycoplasma-induced rash and mucositis (MIRM) is a recently recognized mucocutaneous disorder, often misdiagnosed as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), or erythema multiforme (EM). We report a 6-year-old boy presenting with fever, cough, and cold, followed by painful oral ulcerations, conjunctivitis, genital mucositis, and generalized vesiculobullous rash. He was on levetiracetam for a prior unprovoked seizure, raising suspicion of drug reaction. Initial differentials included SJS, TEN, EM, and Drug reaction with eosinophilia and systemic symptoms. Laboratory findings showed leukocytosis, thrombocytosis, and positive Mycoplasma pneumoniae Immunoglobulin M, while Herpes simplex virus polymerase chain reaction was negative. Histopathology revealed liquefactive necrosis with lymphohistiocytic infiltrates. Despite intravenous antibiotics, antivirals, and immunoglobulin, there was no improvement until pulse methylprednisolone was initiated. He was discharged on tapering oral steroids and doxycycline, with complete mucosal healing on follow-up. As there is no clear-cut distinction between histopathological findings of EM and MIRM, reporting biopsy changes whenever feasible is essential. Early recognition, targeted antibiotics, and timely immunomodulation are key to favorable outcomes.

Treatment for the classical Philadelphia-negative myeloproliferative neoplasms (MPNs), including polycythemia vera (PV) and essential thrombocythemia (ET), has long relied on reducing thrombotic risk without a focus on underlying disease modification. The simplified framework of age and thrombosis history inadequately captures the biological complexity of these diseases with emerging data identifying leukocytosis, elevated neutrophil-to-lymphocyte ratio, and high JAK2 V617F variant allele frequency as independent predictors of thrombotic risk. Furthermore, prognostic models such as MIPSS-PV and MIPSS-ET incorporate somatic mutations to better predict survival. Despite these advances, real-world practice remains anchored to traditional risk categories, with over 30% of high-risk patients receiving no cytoreductive therapy. In this evidence-based review, we trace the evolution of risk stratification in PV and ET and examine the clinical evidence supporting current cytoreductive options, specifically hydroxyurea, interferons, ruxolitinib, and anagrelide. We argue for a paradigm shift away from binarily driven thrombosis-centric risk stratification toward a personalized, proactive approach that integrates molecular and inflammatory biomarkers, expands the population offered cytoreduction, and prioritizes disease-modifying therapies. Prospective studies are needed to validate the incorporation of these markers into risk-adapted algorithms and to define the long-term impact of early disease modification on transformation, survival, and quality of life.

Acquired von Willebrand disease (AvWD) in myeloproliferative neoplasms with extreme thrombocytosis causes paradoxical bleeding due to the mechanism of adsorption and ADAMTS13-mediated proteolysis of high-molecular-weight von Willebrand factor (vWF) multimers. When first-line cytoreductive therapy fails due to intolerance or nonadherence, rapid alternatives are limited. We describe a 74-year-old woman with JAK2V617F-mutated myeloproliferative neoplasm and hydroxyurea intolerance who presented with active mucosal bleeding and a platelet count of 952 000/μL. vWF antigen (vWF:Ag) was 0.37 IU/mL (reference range: 0.50-2.00 IU/mL), and vWF Ristocetin Cofactor activity (vWF:RCo) was 0.21 IU/mL (activity/antigen ratio 0.57; reference range 0.7-1.3), consistent with AvWD. A single thrombocytapheresis session on the Fresenius COM.TEC platform reduced the platelet count to 277 000/μL, with prompt cessation of bleeding. Repeat testing at 24 h showed improvement in vWF:RCo to 0.48 IU/mL (ratio 0.68), which likely reflects restoration of functional high-molecular-weight multimers. In this single case, thrombocytapheresis provided rapid and effective platelet reduction for AvWD secondary to myeloproliferative neoplasms when pharmacological cytoreduction is inadequate.

Myeloproliferative neoplasms (MPNs) are commonly linked to driver mutations in the JAK2, MPL, and CALR genes. In contrast, SH2B3 (LNK) mutations are uncommon and remain an under-characterized contributor to dysregulated JAK-STAT signaling. The clinical features and treatment responsiveness of SH2B3-mutated MPNs are not well defined, and data on outcomes with ropeginterferon alfa-2b in this molecular subgroup are limited. We report a 75-year-old man who presented for evaluation of headache, generalized bone pain, and night sweats and was found to have abnormal blood counts including persistent leukocytosis, erythrocytosis, and thrombocytosis. Prior molecular testing was negative for JAK2, MPL, and CALR mutations. Bone marrow examination showed hypercellularity with panmyelosis, mild megakaryocytic atypia, and WHO grade 1 reticulin fibrosis. Hematologic next-generation sequencing identified a pathogenic SH2B3 c.1481C>G (p.Ser494*) nonsense mutation, predicted to result in a loss of SH2B3's C-terminal regulatory domain. Given the tri-lineage cytoses and marrow findings, a diagnosis of SH2B3-mutated MPN was established. He was started on ropeginterferon alfa-2b, resulting in resolution of his symptoms and complete hematologic response (WBC ≤ 10 × 10[3]/μL, Hct ≤ 45%, and PLT ≤ 400 × 10[3]/μL) within 12 weeks, without the need for phlebotomy or treatment-limiting adverse effects. This case underscores the clinical significance of SH2B3 mutations as a driver of triple-negative MPNs and supports their inclusion in molecular evaluation when classical mutations are absent. The favorable clinical and hematologic response to ropeginterferon alfa-2b suggests that interferon-based therapy may be effective in SH2B3-mutated MPNs.

A female patient diagnosed with an undifferentiated connective tissue disorder (UCTD) experienced progressive symptoms including hair loss, vomiting, diarrhoea and abdominal pain accompanied by haematological changes of anaemia, absolute neutropenia with thrombocytosis following 7 weeks of azathioprine therapy. Consequently, azathioprine was discontinued, resulted in hematologic recovery and hair regrowth. Genetic analysis revealed the presence of an NUDT15 polymorphism, indicating impaired thiopurine metabolism. Hair loss was the first symptom, above all others, indicating an early onset of anagen effluvium as a warning sign of myelotoxicity. The reactive thrombocytosis was attributed to cytokine-mediated inflammation involving IL-1 and IL-6, suggesting a combined haematological response to azathioprine. It is recommended that Clinicians perform a preliminary genetic testing to prevent the need for frequent blood monitoring and to avoid myelotoxicity.

Chronic myeloid leukemia (CML) can rarely present with extreme thrombocytosis as the initial manifestation, a phenotype that can mimic essential thrombocythemia, leading to delayed diagnosis. We describe the case of a 54-year-old woman who was evaluated by outpatient hematology for isolated thrombocytosis with normal iron studies and leukocyte counts. Molecular testing confirmed BCR::ABL1 fusion, consistent with chronic phase CML. She was started on hydroxyurea, but her platelet count continued to rise, requiring hospitalization for close monitoring, where she was initiated on dasatinib, a tyrosine kinase inhibitor (TKI). As her platelets peaked above 4,000 × 109/L (Reference Range [RR]: 150-450 × 109/L), given the high risk of both thrombotic and bleeding complications, she underwent plateletpheresis, which effectively reduced counts before TKI therapy could achieve disease control. This case highlights the importance of considering the diagnosis of CML in patients with isolated thrombocytosis, particularly in women, and emphasizes the role of plateletpheresis as a potential preventive bridge until TKI therapy takes effect.

Objective Transient abnormal myelopoiesis (TAM) is a self-limited clonal myeloproliferative disorder seen almost exclusively in neonates with trisomy 21 and defined by circulating myeloblasts carrying N-terminal truncating GATA1 mutations. Although most cases occur in infants with typical Down syndrome features, TAM can arise in clinically normal newborns with mosaic trisomy 21, creating significant diagnostic uncertainty. Study Design We report a term female neonate who presented with pallor, respiratory distress, hepatosplenomegaly, and a papular, nonblanching rash. Results Laboratory studies showed marked thrombocytosis, leukocytosis, and numerous circulating blasts. Flow cytometry detected a 17% abnormal blast population resembling congenital acute myeloid leukemia, but bone marrow aspirate revealed a myeloproliferative picture without definitive malignancy, favoring TAM. Molecular testing confirmed a truncating GATA1 mutation and mosaic trisomy 21 by SNP array, fluorescence in situ hybridization, and microarray. The infant's condition improved rapidly, with resolution of organomegaly and normalization of blood counts in the first week of life. Conclusion This case underscores the diagnostic challenges of TAM in phenotypically normal infants. Because clinical and laboratory findings can closely mimic congenital leukemia, early evaluation for GATA1 mutations and trisomy 21 is essential to establish the correct diagnosis, guide management, and avoid unnecessary chemotherapy.

Urticaria multiforme (UM) is a benign hypersensitivity reaction of early childhood characterized by transient annular urticarial plaques with dusky centers and acral edema. Although self-limited, UM is frequently misdiagnosed as serum sickness-like reaction (SSLR), erythema multiforme (EM), or urticarial vasculitis due to overlapping features such as fever, edema, and inflammatory laboratory abnormalities. Diagnostic uncertainty may therefore lead to extensive investigations, hospitalization, and unnecessary systemic corticosteroid therapy. A three-year-old male with a history of atopic dermatitis presented with decreased oral intake, lethargy, fever, and intermittent erythematous wheals associated with swelling of the feet and extremities. Initial evaluation revealed influenza A (H3) infection, thrombocytosis, and mildly elevated C-reactive protein. Extensive diagnostic evaluation, including multiple imaging studies and laboratory investigations, was largely unremarkable except for preserved complement levels. Due to concern for a serum sickness-like reaction, systemic corticosteroids were initiated. The dermatology consultation subsequently favored urticaria multiforme based on the transient nature of lesions lasting less than 24 hours, absence of mucosal involvement or palpable purpura, preserved complement levels, and progressive clinical improvement. The patient was managed with antihistamines and supportive care, with complete resolution of fever, edema, and urticarial lesions prior to discharge after a hospital course of six days. This case highlights influenza-associated urticaria multiforme presenting with fever and mild inflammatory marker elevation, closely mimicking immune complex-mediated disease. Recognition of lesion duration, morphology, and complement preservation is essential for accurate diagnosis and to prevent unnecessary immunosuppressive therapy.

Pertussis is a common infectious disease affecting both children and adults. In young infants, it can cause severe respiratory illness associated with prolonged hospitalization and high mortality, particularly in cases complicated by severe leukocytosis and lymphocytosis, which increase the risk of pulmonary hypertension and multiorgan failure. Exchange transfusion remains the traditional first-line treatment for severe pertussis-associated hyperleukocytosis. However, in centers with appropriate resources and expertise, leukapheresis may be considered as an alternative therapeutic option. Leukapheresis enables selective reduction of circulating white blood cells, which are thought to play a central role in the pathophysiology of severe pertussis, while avoiding exposure to allogeneic blood products. It may also result in incidental platelet removal, potentially reducing blood viscosity and thrombotic risk in patients with concomitant thrombocytosis. Despite these potential advantages, leukapheresis is technically demanding and should be performed only in experienced centers with established protocols and appropriate expertise. Through the apheresis system we treated two patients who developed malignant pertussis with which successfully decreased their WBC counts by more than 50%. In the presence of limited guidance in the current literature regarding its prescription, usage, and safety specifically in pertussis, this report provides additional insights into the prescription and implementation of an effective leukocyte depletion.