We report a 15-year-old boy from Karnataka, India, initially misdiagnosed as HbE/β-thalassemia. On follow-up, Capillary electrophoresis (CE) showed a 3.3% peak in Zone 4, with the WBC Differential Fluorescence (WDF) scattergram on the Sysmex XN 10 instrument suggesting an unstable hemoglobin. CE pattern, along with heat stability testing, mass spectrometry, and molecular sequencing, confirmed Hb Köln (β98 Val → Met), also detected in his father. This case emphasizes the need to suspect unstable hemoglobins in unexplained hemolysis and highlights the diagnostic value of CE and WDF scattergram.

Acute myeloid leukemia (AML) is characterized by myeloid blasts in the bone marrow and peripheral blood, and it is a highly heterogenous disease genetically. Although our understanding of AML genetics has advanced considerably, disease relapse continues to pose a significant therapeutic hurdle.

18-Fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) scans have largely replaced bone marrow biopsy in the staging workup for diffuse large B-cell lymphoma (DLBCL).

The Triple A model has recently been developed and validated in essential thrombocythemia (ET) and polycythemia vera (PV). However, external validation in diverse populations remains unclear.

Heparin-induced thrombocytopenia (HIT) is a life-threatening immunologic reaction to heparin exposure that is associated with substantial morbidity and mortality. Limited research is available on host-dependent risk factors, such as age, gender, and ethnicity. This study aims to characterize any association between age, gender, ethnicity, and mortality in HIT patients to better identify patient populations at increased risk.

Castleman disease is an uncommon lymphoproliferative disorder that usually involves lymph nodes but can rarely present in extranodal sites. We describe an unusual case of Castleman disease exclusively involving the kidney. The authors also briefly discuss previously documented clinicopathological and radiological characteristics associated with Castleman disease of the kidney.We report a case of a 57-year-old female who presented with persistent abdominal pain. Imaging revealed a 1.8-cm nodule in the upper pole of the left kidney with no evidence of systemic lymphadenopathy. A nephrectomy was performed due to concerns for a primary renal neoplasm. Histopathological evaluation was consistent with hyaline vascular Castleman disease of the kidney (unicentric). The patient has remained stable for the past 3 years with no new development of lesions.Primary Castleman disease of the kidney is an uncommon entity that can present with various clinical and radiological features. Our case, along with previously reported cases, highlights the diagnostic challenges of these lesions, especially in distinguishing them from primary renal neoplasms during radiological evaluation. A comprehensive clinical and histopathological assessment is essential for establishing a diagnosis.

IgG4 plasma cells are well-known in the context of IgG4-related disease (IgG4-RD). Meanwhile, their role in other disorders remains enigmatic. In hematopathology practice, the presence of these cells can be non-specific in reactive lymphadenopathy, requiring clinicopathological correlation to exclude IgG4-RD. A high density of IgG4 plasma cells may help distinguish progressive transformation of germinal centers from early nodular lymphocyte-predominant Hodgkin lymphoma. IgG4 plasma cells are also present in a subset of classic Hodgkin lymphomas, particularly the nodular sclerosis subtype. Despite their morphological similarities, Rosai-Dorfman disease and IgG4-RD appear to be distinct entities. Idiopathic multicentric Castleman disease and IgG4-RD can be histologically indistinguishable, which necessitates clinical and laboratory differentiation. Marginal zone lymphoma and, rarely, myeloma can express IgG4, with some cases of marginal zone lymphoma having concurrent IgG4-RD. This review provides a comprehensive analysis of IgG4 plasma cells in hematopathology and discusses their diagnostic significance and associated challenges.

Background Myeloid/lymphoid neoplasm with eosinophilia and rearrangement of FGFR1(MLN-FGFR1), also referred to as 8p11 myeloproliferative syndrome (EMS), arises from aberrant FGFR1 gene rearrangement in bone marrow hematopoietic stem cells, resulting in the transformation of myeloid/lymphoid cells into neoplastic growths. The clinical and laboratory features of affected individuals are influenced by the specific partner genes. Purpose This article aims to report a case of MLN-FGFR1 involving a novel CNTRL::FGFR1 splicing variant and to discuss its clinicopathological characteristics and treatment challenges. Methods/Results We report a case of MLN-FGFR1 in a 35-year-old male patient presenting with leukocytosis, lymphadenopathy, hepatosplenomegaly, and a mixed population of B lymphoblasts, T lymphoblasts, and monoblasts in the bone marrow and lymph nodes. Comprehensive molecular profiling, including chromosomal karyotyping, fluorescence in situ hybridization (FISH), targeted transcriptome sequencing, reverse transcription polymerase chain reaction (RT-PCR), and Sanger sequencing, identified a novel splicing variant of the CNTRL::FGFR1 fusion, resulting from a t(8;9)(p11;q33) translocation. This novel splicing variant involves an in-frame fusion between exon 38 of CNTRL and exon 11 of FGFR1, retaining the kinase domain of FGFR1 and leading to its constitutive activation. Despite multiple treatment regimens, the patient failed to achieve complete remission (CR). Conclusion The findings highlight the urgent need for targeted therapies, such as FGFR inhibitors, to improve outcomes in patients with FGFR1-rearranged malignancies.

Trephine bone marrow biopsies (TBMB) are standard specimens for diagnostics and follow-up of myeloid and precursor cell neoplasms, usually as part of a multimodal approach including complete blood count (CBC) tests, cytologic assessment of BM aspirate smears, flow cytometry, cytogenomics, and molecular genetics. Incorporating the results of all the above methods or running all tests within one specialized lab and providing an integrative report is ideally desirable. However, in reality, in many countries, (1) diagnostic (hemato-)pathologists may not have access to information on the results obtained by other technologies except for a CBC, (2) individual procedures may not be available at all, (3) specimens may not be submitted to specialized labs, or (4) particular technologies may fail yielding results (e.g., dry taps or specimens with destroyed nucleic acids), so that the TBMB might remain the only analytic sample. The detailed description of our approach to handling TBMB including classic histopathology, immunohistochemistry, fluorescence in situ hybridization, and sequencing techniques in the setting of myeloid and precursor neoplasms may help the readership to achieve a comprehensive TBMB diagnostic approach reaching more definite and robust conclusions to improve patient care.

Myeloid and/or lymphoid neoplasms with eosinophilia PDGFRA gene fusions usually occur with FIP1L1 as the partner gene; however, novel partners have been described. These novel partners are sometimes responsive to tyrosine kinase inhibitor therapy.

We collected 97 cases of myeloid neoplasia with the rare cytogenetic event of isolated trisomy 19 (+19), with the aim to characterize this group clinically and pathologically. 51 patients with myelodysplastic syndrome (MDS +19) and 11 patients with myelodysplastic/myeloproliferative neoplasms (MDS/MPN +19) presented with +19 at disease onset and were further analyzed. Patients with insufficient data were excluded. We collected additional clinical and laboratory data and performed mutation analysis on available bone marrow biopsies. The 62 patients of both disease groups turned out to be remarkably homogeneous in terms of male sex (85%), the presence of anemia with increased numbers of ring sideroblasts (RS, 80%), the absence of an SF3B1 mutation (95%), and the overall rather consistent presence of SRSF2 (61%) or ASXL1 (39%) mutations. MDS +19 patients with available follow-up (1 month to 7.5 years) presented or progressed with significant fibrosis (45%), leuko- or monocytosis (13%) or acute leukemia (28%). Compared to a control cohort of 23 patients with MDS and an SRSF2 mutation, but without isolated +19 (MDS-SRSF2), the 16 MDS +19 patients with SRSF2 mutation and the 12 MDS +19 patients with an ASXL1 mutation showed a striking difference in the presence of ≥ 15% RS (73% and 67% versus 17% in MDS-SRSF2) and the occurrence of fibrosis (44% and 57% versus 4% in MDS-SRSF2). Although all individual features observed in the MDS +19 and MDS/MPN +19 cohorts are seen in MDS and MDS/MPN in general, their combination is rather unique and provides clues regarding disease evolution in this rare, cytogenetically defined group of myeloid neoplasia.

The interpretation of lymph node biopsy is influenced by factors inherent to the type of biopsy. In recent times, core needle biopsies (CNB) have increasingly been preferred over whole node excision (WNE) for sampling lymph nodes.

This study evaluated immune cell subset variations in immune thrombocytopenia (ITP) by comparing frequencies at diagnosis with controls and assessing changes post-therapy. A single-center prospective observational study enrolled 25 untreated acute and chronic ITP patients and 20 matched controls from January 2018 to January 2019. Immune cell subsets, including CD4+, CD8+, NK cells, NK-T cells, and T regulatory cells (Tregs), were analyzed using flow cytometric immunophenotyping. Patients received standard therapy, with responses assessed after 1 month using international criteria. The median age of patients was 43 years, with 52% female. At diagnosis, patients exhibited significantly lower Tregs (p = 0.001) and NK-T cells (p = 0.017), higher CD8+ cytotoxic T-cells, and a reduced CD4/CD8 ratio (p = 0.001) compared to controls. Following therapy, 85% of patients responded: 45% achieved complete response, and 40% partial response. However, post-treatment immune cell subsets did not differ significantly from baseline, nor could they predict response. ITP patients display notable immune cell abnormalities compared to controls, though these differences do not serve as reliable predictors of treatment outcomes. Further large-scale studies with functional analyses are essential to elucidate ITP pathogenesis and identify therapeutic targets.

Current classification systems for myelodysplastic syndromes (MDS) incorporate morphologic findings, blast percentage, and some genetic features such as del(5q) and SF3B1 and TP53 mutations. A recent comprehensive molecular taxonomy proposed by the MDS-International Working Group (MDS-IWG) categorizes MDS into 16 molecular groups and two residual groups and describes associations with various clinicopathological features and differing overall survival among groups.

In situ follicular neoplasia (ISFN) is characterized by a monoclonal proliferation of BCL2-positive B cells harboring the translocation t(14;18)(q32;q21). These cells are confined to follicle centers and are usually identified incidentally, with a very low risk of progression to follicular lymphoma. Sebaceous lymphadenoma is a rare, benign salivary gland tumor, most commonly arising in the parotid gland, and is histologically defined by solid epithelial nests and cysts with sebaceous differentiation in a hyperplastic lymphoid stroma. We report an unusual case of ISFN arising within a sebaceous lymphadenoma. To the best of our knowledge, this association has not previously been reported.

The pluripotency of malignant blasts in acute leukemias is a growing area of scientific and clinical interest. Mixed-phenotype acute leukemias (MPALs) are defined by the presence of blasts showing evidence of differentiation along at least two lineages. Curiously, MPALs exhibit some of the same recurrent cytogenetic abnormalities (e.g., BCR::ABL1, KMT2A rearrangements) that are seen in single-lineage acute leukemias. Factors that contribute to phenotypic selection and divergence of blast populations in single-lineage and mixed-phenotype acute leukemias are incompletely understood. Optimal therapeutic management of MPAL also remains a matter of debate. Herein, we present a case of MPAL with BCR::ABL1 fusion that showed distinct T-lymphoblastic and B-lymphoblastic/myeloblastic populations at different anatomic sites (tonsil and bone marrow, respectively). Both blast populations showed clonally related TRG rearrangements with evidence of clonal evolution. The patient initially responded to tyrosine kinase inhibitor therapy, but he quickly relapsed and expired a year after diagnosis. To our knowledge, this is the first time an MPAL has been shown to have different blast lineages segregated to distinct anatomic sites in a treatment-naïve patient. This case emphasizes the importance of a multifaceted diagnostic approach to acute leukemias and highlights what is left to learn about the biology and management of these poorly understood neoplasms.

Myelomastocytic leukemia (MML) presenting as a blast phase manifestation of Chronic Myeloid Leukemia (CML) is exceptionally rare, with limited documented cases in the literature. Understanding its distinct clinicopathologic features and treatment outcomes is crucial for optimal patient management. A 45-year-old male with a history of CML since 2016, previously treated with imatinib and dasatinib, presented after treatment interruption with leukocytosis (WBC 27.3 × 103/μL) and 58% circulating blasts showing metachromatic granulation. Bone marrow examination revealed 30% blast cells with strong CD117 and tryptase positivity. Flow cytometry identified two distinct populations: 7% myeloblasts and 27% immature myeloid cells with bright CD117 expression. BCR-ABL1 rearrangement was confirmed with a ratio of 112% (IS). The patient received combination therapy with standard "3 + 7" induction chemotherapy and dasatinib. Despite complications of febrile neutropenia, the post-induction bone marrow examination demonstrated achievement of complete morphologic remission. This case highlights the successful initial treatment of myelomastocytic transformation in CML blast phase using intensive combination therapy. The detailed morphologic, immunophenotypic and molecular characterization provides valuable insights into this rare entity, while the favorable initial response supports an aggressive treatment approach. Long-term follow-up and further studies are needed to establish optimal treatment strategies.

Multiple myeloma (MM) is a malignant neoplasm of clonal plasma cells, typically associated with the production of a monoclonal protein. In 1-3% of cases, MM presents without measurable monoclonal protein (M protein) in the serum or urine and normal serum-free light chains; these cases are referred to as non-secretory MM (NSMM). This definition has changed over time according to the sensitivity of laboratory methods for detecting paraproteins. NSMM has been previously reported to have a less aggressive presentation and clinical course compared to secretory MM; however, the literature is conflicting. Recent studies have indicated that NSMM may exhibit different responses to therapy and outcomes, emphasizing the need for a tailored approach. This review consolidates the current understanding of NSMM and underscores the importance of advanced diagnostic techniques in improving patient management and outcomes.

Intron 22 inversion (Inv22) of the factor VIII gene (F8) accounts for approximately 45% of severe hemophilia A (HA) cases. Detecting Inv22 has become the primary screening method for severe HA. Currently, agarose gel electrophoresis (AGE) following long-distance polymerase chain reaction (LD-PCR) is commonly used in clinical settings to separate the amplified fragments of Inv22. However, AGE is hindered by lengthy processing times, instability, and inaccuracies in quantifying DNA content and assessing fragment sizes. We combined LD-PCR with capillary gel electrophoresis (CGE) for the identification of Inv22 in HA. Three primers were designed for LD-PCR to differentiate between Inv22, carriers, and wild types. We optimized the reaction system and conditions for CGE to effectively separate the amplified fragments. The optimal dilution ratio and buffer conditions for detecting Inv22 using CGE were 300 × and 0.1 × TE buffer. The ideal voltage and duration were 5.0 kV for 80 min. Under these conditions, the amplified fragments could be effectively separated, allowing for the direct measurement of concentration and size of the target fragments using ProSize data analysis software. The LD-PCR combined with the CGE assay for detecting Inv22 in F8 within HA populations has been successfully established. This method reduces both the time and labor required for detecting Inv22 in clinical practice, thereby advancing genetic diagnostic technology for hemophilia.

Alpha globin chain variants constitute a very small fraction of the total hemoglobinopathy cases. Their rarity and the often-unfamiliar elution times/patterns in high performance liquid chromatography (HPLC) that mimic those of normal hemoglobin (Hb) fractions and/or known beta globin variants render their primary diagnosis difficult. We describe here Hb Fontainebleau, a rare alpha globin chain variant, in an adult female that eluted in the HbA2 window in a less commonly used HPLC platform, Lifotronic H8, thereby causing difficulties in the diagnosis. The matter was resolved by running the sample on a more commonly used platform wherein the abnormal Hb yielded a familiar elution time and pattern known to be associated with Hb Fontainebleau. This was further confirmed by gene sequencing, which showed a Codon 21 (G → C); HBA2:c.64G > C (or HBA1) mutation. A literature search failed to reveal any published case of the unique elution pattern of Hb Fontainebleau on Lifotronic H8 HPLC platform and the associated diagnostic challenges. An increasing use of the newer HPLC platforms calls for greater awareness of these issues.