Myeloid sarcomas with CBFA2T3 : GLIS2 fusion: clinicopathologic characterization of 4 cases mimicking small round cell tumors.

Objectives: Acute myeloid leukemia with CBFA2T3::GLIS2 fusion can initially present as extramedullary lesions (myeloid sarcoma), leading to a misdiagnosis of nonhematologic pediatric solid tumors.

Methods: We characterized the clinicopathologic features of 4 cases of CBFA2T3::GLIS2 fusion-positive myeloid sarcoma in pediatric patients where the sarcoma presented either without leukemic involvement (isolated myeloid sarcoma; 3/4 [75%]) or had concurrent leukemic disease (1/4 [25%]).

Results: All cases mimicked nonhematopoietic tumors at morphologic and immunophenotypic levels, so the initial evaluation did not raise suspicion for acute myeloid leukemia/myeloid sarcoma.

Simultaneous Presentation of B-Acute Lymphoblastic Leukemia and Streptococcus agalactiae Meningitis in a 3-Year-old Girl.

Infection is a major cause of treatment-related morbidity and mortality in pediatric acute lymphoblastic leukemia (ALL). Most children with ALL who develop life-threatening bacterial infections do so during induction therapy. We describe a rare case of ALL presenting simultaneously with Streptococcus agalactiae group B Streptococcus bacteremia and meningitis in a 3-year-old girl.

tandem duplications in pediatric myelodysplastic syndrome and acute myeloid leukemia: implications for clinical screening and diagnosis.

Recent genomic studies in adult and pediatric acute myeloid leukemia (AML) demonstrated recurrent in-frame tandem duplications (TD) in exon 13 of upstream binding transcription factor (UBTF). These alterations, which account for approximately 4.3% of AML in childhood and about 3% in adult AML aged <60 years of age, are subtype-defining and associated with poor outcomes.

Tandem Duplications in Pediatric MDS and AML: Implications for Clinical Screening and Diagnosis.

Recent genomic studies in adult and pediatric acute myeloid leukemia (AML) demonstrated recurrent in-frame tandem duplications (TD) in exon 13 of upstream binding transcription factor (). These alterations, which account for ~4.3% of AMLs in childhood and up to 3% in adult AMLs under 60, are subtype-defining and associated with poor outcomes.

-positive acute leukemia with RAM and mixed T/megakaryocytic phenotype.

Herein, we present a rare case of acute myeloid leukemia (AML) with CBFA2T3-rearrangement and the expression of megakaryocytic and lymphoid markers, highlighting the need for a high suspicion index in differential diagnosis and applying adequate workup to avoid misdiagnosing this entity. -positive AML is primarily found in infants with non-down syndrome acute megakaryoblastic leukemia (non-DSAMKL). Flow cytometry immunophenotyping plays an important role in recognizing the unique immunophenotype of bright CD56 expression with dim/negative expression of HLA-DR, CD38, and CD45 termed the RAM immunophenotype in this entity.

Blastoid B-Cell Neoplasms: Diagnostic Challenges and Solutions.

Blastoid B-cell neoplasms mainly include B-lymphoblastic leukemia/lymphoma (B-ALL), blastoid mantle cell lymphoma, and high-grade B-cell lymphoma with blastoid morphologic features (blastoid HGBL). Distinguishing blastoid HGBL from B-ALL can be challenging and we previously developed six-point flow cytometry-focused and three-point immunohistochemistry-focused scoring systems to aid in differential diagnosis. However, the six-point scoring system was derived from bone marrow cases and occasional cases may have a misleading score using either system.

Engineering naturally occurring CD7- T cells for the immunotherapy of hematological malignancies.

Chimeric antigen receptor (CAR) T-cell therapy targeting T-cell acute lymphoblastic leukemia (T-ALL) faces limitations such as antigen selection and limited T-cell persistence. CD7 is an attractive antigen for targeting T-ALL, but overlapping expression on healthy T cells leads to fratricide of CD7-CAR T cells, requiring additional genetic modification. We took advantage of naturally occurring CD7- T cells to generate CD7-CAR (CD7-CARCD7-) T cells.

Bone marrow clonal hematopoiesis is highly prevalent in blastic plasmacytoid dendritic cell neoplasm and frequently sharing a clonal origin in elderly patients.

Myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML) are reported in up to 20% patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN), where a shared clonal origin is shown in individual case studies. In this study, we performed targeted next generating sequencing on multiple bone marrow (BM), skin or sorted cells from 51 BPDCN patients (68.7 years,14.

The Leukemic Phase of ALK-Negative Anaplastic Large Cell Lymphoma Is Associated with CD7 Positivity, Complex Karyotype, Deletion, and a Poor Prognosis.

Patients with anaplastic large cell lymphoma (ALCL) rarely develop a leukemic phase of the disease. The reported leukemic ALCL cases are almost all ALK-positive, which are frequently associated with small cell morphology, t(2;5)(p23;q35), and a poorer prognosis. Rare leukemic ALK-negative ALCL cases have been reported.

Follicular lymphoma: updates for pathologists.

Follicular lymphoma (FL) is the most common indolent B-cell lymphoma and originates from germinal center B-cells (centrocytes and centroblasts) of the lymphoid follicle. Tumorigenesis is believed to initiate early in precursor B-cells in the bone marrow (BM) that acquire the t(14;18)(q32;q21). These cells later migrate to lymph nodes to continue their maturation through the germinal center reaction, at which time they acquire additional genetic and epigeneticabnormalities that promote lymphomagenesis.

Value and pitfalls of assessing bone marrow morphologic findings to predict response in patients with myelofibrosis who undergo hematopoietic stem cell transplantation.

Background: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative option for patients with myelofibrosis (MF). Bone marrow (BM) morphologic evaluation of myelofibrosis following allo-HSCT is known to be challenging in this context because resolution of morphologic changes is a gradual process.

Patients And Methods: We compared BM samples of patients with myelofibrosis who underwent first allo-HSCT and achieved molecular remission by day 100 with BM samples of patients who continued to have persistent molecular evidence of disease following allo-HSCT.

Mantle cell lymphoma with chronic lymphocytic leukemia-like features: a diagnostic mimic and pitfall.

Mantle cell lymphoma (MCL) is a mature B-cell neoplasm characterized by t(11;14) (q13;q32) and cyclin D1 overexpression in >95% of cases. Classic MCL cases are composed of a monotonous population of small- to medium-sized lymphocytes with irregular nuclear contours that are positive for cyclin D1 and SOX11 and negative for CD23 and CD200. By contrast, occasional MCL cases express CD23 and CD200 but lack SOX11 and morphologically and immunophenotypically resemble chronic lymphocytic leukemia (CLL), termed as CLL-like MCL in this study.

Small cell/lymphohistiocytic morphology is associated with peripheral blood involvement, CD8 positivity and retained T-cell antigens, but not outcome in adults with ALK+ anaplastic large cell lymphoma.

Several morphologic variants of ALK+ anaplastic large cell lymphoma (ALCL) are recognized. The small cell (SC) and lymphohistiocytic (LH) variants are reported to be associated with poorer outcome in children with ALK + ALCL. In this study of 102 adults with ALK + ALCL, there were 18 (18%) cases of SC and/or LH variants.

Blastoid high-grade B-cell lymphoma initially presenting in bone marrow: a diagnostic challenge.

The 2016 WHO classification introduced the category of high-grade B-cell lymphoma (HGBL), which includes one poorly understood subset, blastoid-HGBL. Establishing the diagnosis and distinguishing blastoid-HGBL from B-acute lymphoblastic leukemia (B-ALL) in bone marrow can be challenging. We assessed 31 cases of blastoid-HGBL diagnosed initially in bone marrow and compared this group to 36 cases of B-ALL using immunophenotyping, fluorescence in situ hybridization, and targeted next generation sequencing analysis.

ETV4 and ETV5 drive synovial sarcoma through cell cycle and DUX4 embryonic pathway control.

Synovial sarcoma is an aggressive malignancy with no effective treatments for patients with metastasis. The synovial sarcoma fusion SS18-SSX, which recruits the SWI/SNF-BAF chromatin remodeling and polycomb repressive complexes, results in epigenetic activation of FGF receptor (FGFR) signaling. In genetic FGFR-knockout models, culture, and xenograft synovial sarcoma models treated with the FGFR inhibitor BGJ398, we show that FGFR1, FGFR2, and FGFR3 were crucial for tumor growth.