Optical genomic mapping is a helpful tool for detecting CCND1 rearrangements in CD5-negative small B-cell lymphoma: Two cases of leukemic non-nodal mantle cell lymphoma.

Optical genome mapping (OGM) is a new DNA-based technology which provides comprehensive examination of the entire genome. We report two patients who presented with splenomegaly and leukocytosis with lymphocytosis including villous lymphocytes. Neither patient had lymphadenopathy. Bone marrow evaluation showed involvement by small B-cell lymphoma in a sinusoidal and interstitial distribution, and immunophenotypic analysis showed that the neoplastic cells were positive for B-cell markers and cyclin D1 but were negative for SOX11 and CD5. Initially, the clinicopathologic features in both patients were thought to be suspicious for hairy cell leukemia variant or splenic marginal zone lymphoma. However, OGM detected CCND1 rearrangement: t(2;11)/IGK::CCND1 in one case and t(11;14)/IGH::CCND1 in the other case. These cases illustrate the valuable role OGM can play in establishing the diagnosis of MCL. Case 1 also contributes to the paucity of literature on the rare occurrence of IGK::CCND1 in MCL.

Frontline Hyper-CVAD Plus Venetoclax for Pediatric Blastic Plasmacytoid Dendritic Cell Neoplasm.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy, especially in pediatrics, that can involve the bone marrow, skin, lymph nodes, and central nervous system (CNS). Given its variable clinical presentation, coupled with an immunohistochemistry pattern (CD4, CD56, TCF4, TCL-1, and CD123 positivity) that differs from other myeloid neoplasms, the diagnosis of BPDCN can be missed. Limited data are available to guide the treatment of pediatric BPDCN. Herein, we report a case of a pediatric patient who had BPDCN with central nervous system, orbital, and skin involvement. This patient achieved complete remission after receiving modified hyper-CVAD (hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone with venetoclax and intrathecal chemotherapy. He remains disease-free 200 days after receiving a stem cell transplant. This represents the first known published pediatric case using a modified hyper-CVAD plus venetoclax regimen for treating a pediatric BPDCN patient in the frontline setting.

Gastric Myeloid Sarcoma.

Most gastric cancers are adenocarcinomas, but other malignancies can arise in the stomach. Patients with leukemia may develop myeloid sarcoma (MS) in the gastrointestinal tract. Our patient was a 68-year-old woman who was initially diagnosed with acute myeloid leukemia and underwent a matched unrelated stem cell transplantation. She was in remission for 10 years before developing a rare case of gastric MS without acute myeloid leukemia. She had partial response to chemotherapy but ultimately died because of infection. Gastric MS has an incidence of less than 1%. Gastrointestinal involvement usually involves the small intestine and rarely the stomach.

Blastic plasmacytoid dendritic cell neoplasm: a comprehensive review in pediatrics, adolescents, and young adults (AYA) and an update of novel therapies.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy that can involve the bone marrow, peripheral blood, skin, lymph nodes, and the central nervous system. Though more common in older adults, BPDCN has been reported across all age groups, including infants and children. The incidence of pediatric BPDCN is extremely low and little is known about the disease. Pediatric BPDCN is believed to be clinically less aggressive but often with more dissemination at presentation than adult cases. Unlike adults who almost always proceed to a hematopoietic stem cell transplantation in first complete remission if transplant-eligible, the majority of children can be cured with a high-risk acute lymphoblastic leukemia-like regimen. Hematopoietic stem cell transplantation is recommended for children with high-risk disease, the definition of which continues to evolve, or those in relapse and refractory settings where outcomes continue to be dismal. Novel agents used in other hematologic malignancies and CD123 targeted agents, including chimeric antigen receptor T-cells and monoclonal/bispecific antibodies, are being brought into research and practice. Our goal is to provide a comprehensive review of presentation, diagnosis, and treatment by review of pediatric cases reported for the last 20 years, and a review of novel targeted therapies and therapies under investigation for adult and pediatric patients.

Clinicopathologic Features of Therapy-Related Myeloid Neoplasms in Patients with Myeloma in the Era of Novel Therapies.

The development of therapy-related myeloid neoplasms (t-MN) is a rare complication that can occur in myeloma patients treated primarily with novel therapies. To better understand t-MNs in this context, we reviewed 66 such patients and compared them with a control group of patients who developed t-MN after cytotoxic therapies for other malignancies. The study group included 50 men and 16 women, with a median age of 68 years (range, 48-86 years). Therapies included proteasome inhibitors, immunomodulatory agents, and high-dose melphalan-based autologous stem cell transplantation (HDM-ASCT) in 64 (97%), 65 (98.5%), and 64 (97%) patients, respectively; 29 (43.9%) patients were exposed to other cytotoxic drugs besides HDM. The latency interval from therapy to t-MN was 4.9 years (range, 0.6-21.9 years). Patients who received HDM-ASCT in addition to other cytotoxic therapies had a longer latency period to t-MN compared with patients who only received HDM-ASCT (6.1 vs 4.7 years, P = .009). Notably, 11 patients developed t-MN within 2 years. Therapy-related myelodysplastic syndrome was the most common type of neoplasm (n = 60), followed by therapy-related acute myeloid leukemia (n = 4) and myelodysplastic syndrome/myeloproliferative neoplasm (n = 2). The most common cytogenetic aberrations included complex karyotypes (48.5%), del7q/-7 (43.9%), and/or del5q/-5 (40.9%). The most frequent molecular alteration was TP53 mutation, in 43 (67.2%) patients and the sole mutation in 20 patients. Other mutations included DNMT3A, 26.6%; TET2, 14.1%; RUNX1, 10.9%; ASXL1, 7.8%; and U2AF1, 7.8%. Other mutations in less than 5% of cases included SRSF2, EZH2, STAG2, NRAS, SETBP, SF3B1, SF3A1, and ASXL2. After a median follow-up of 15.3 months, 18 patients were alive and 48 died. The median overall survival after the diagnosis of t-MN in the study group was 18.4 months. Although the overall features are comparable to the control group, the short interval to t-MN (<2 years) underscores the unique vulnerable status of myeloma patients.

An update on genetic aberrations in T-cell neoplasms.

T-cell neoplasms are a highly heterogeneous group of leukaemias and lymphomas that represent 10-15% of all lymphoid neoplasms. Traditionally, our understanding of T-cell leukaemias and lymphomas has lagged behind that of B-cell neoplasms, in part due to their rarity. However, recent advances in our understanding of T-cell differentiation, based on gene expression and mutation profiling and other high throughput methods, have better elucidated the pathogenetic mechanisms of T-cell leukaemias and lymphomas. In this review, we provide an overview of many of the molecular abnormalities that occur in various types of T-cell leukaemia and lymphoma. Much of this knowledge has been used to refine diagnostic criteria that has been included in the fifth edition of the World Health Organization. This knowledge is also being used to improve prognostication and identify novel therapeutic targets, and we expect this progress will continue, eventually resulting in improved outcomes for patients with T-cell leukaemias and lymphomas.

From the archives of MD Anderson Cancer Center: Aleukemic T-prolymphocytic leukemia, a rare presentation and review of the literature.

T-prolymphocytic leukemia (T-PLL) is a rare, aggressive T-cell leukemia, and patients typically present with marked peripheral blood lymphocytosis. Approximately 15-20 % of patients may present with moderate and relative stable lymphocytosis and an indolent clinical course that can persist for a few years. However, eventually these patients go on to develop marked lymphocytosis and rapidly progressive disease. We report a 72-year-old man who presented with multicompartmental lymphadenopathy and a normal complete blood count. Excision of left and right cervical lymph nodes showed replacement of the lymph node architecture by a small T-cell neoplasm positive for CD3, CD4, CD5, CD7 and TCL-1, and negative for CD8, CD20, CD30 and ALK. Subsequent bone marrow evaluation showed minimal bone marrow involvement by a T-cell neoplasm associated with TCL1A rearrangement in 11 % of cells supporting the diagnosis of T-PLL. Despite treatment, he showed progressive lymphadenopathy while remarkably maintaining normal white blood cell counts until he eventually developed leukocytosis of 110.9 × 103/uL 26 months later. Review of the literature identified only a single abstract reporting a patient with a similar lymphoma-like presentation and normal white blood cell count; however, that case showed significant bone marrow involvement in stark contrast to the current case. In summary, we report a highly unusual case of T-PLL can initially presenting with an aleukemic or lymphoma-like clinical picture, which can make establishing the diagnosis challenging.

Lymphoplasmacytic lymphoma with IgG or IgA paraprotein: a study of 29 cases including cases that can mimic plasma cell neoplasms.

Lymphoplasmacytic lymphoma (LPL) with IgG or IgA paraprotein is rare and a subset of cases can mimic a plasma cell neoplasm (PCN). We studied 29 such cases to explore their clinicopathological features and the best diagnostic approaches with a focus on bone marrow findings. The cohort included 18 men and 11 women with a median age of 68 years. The median M protein was 3.1 g/dL, IgG in 19 patients (66%), IgA in 9 (31%), and dual IgG/IgA in 1 (3%). All patients had bone marrow involvement with CD138+ plasma cells (PCs) ranging from 1 to 35% (median, 10%). Two patients also had amyloidosis. Immunoglobulin light chain concordant monotypic PCs and monotypic B cells were identified in 96% of cases assessed by flow cytometry. Notably, the neoplastic PCs were consistently positive for CD45 (dim, 100%), CD19 (96%), CD81 (89%), CD27 (83%), rarely and only weakly or partially express CD56 (16%), whereas CD117 was consistently negative. Eleven cases analyzed by fluorescence in situ hybridization were negative for CCND1::IGH and myeloma-related aberrations. MYD88 mutation was detected in 17 of 24 cases (71%), and CXCR4 mutation was identified in 6 of 19 cases (32%), of which 4 had concurrent MYD88 mutation. In conclusion, the results highlight a potential diagnostic pitfall of LPL associated with marked plasmacytic differentiation and an IgG or IgA paraprotein that can resemble a PCN. Useful features in favor of LPL against PCN include the characteristic immunophenotypic profile of the PCs in LPL, absence of CCND1::IGH, and the presence of MYD88 and/or CXCR4 mutations.

Primary mediastinal germ cell tumor and clonally related and unique hematologic neoplasms with i(12p) and TP53 mutation: A report of two cases.

The development of clonally related hematologic neoplasms in the setting of primary mediastinal germ cell tumors (PMGCTs) has been recognized previously and is associated with a dismal prognosis. However, the presentation of hematologic neoplasms as chronic myelomonocytic leukemia (CMML) and hemophagocytic lymphohistiocytosis (HLH) has been rarely reported. Here we report two patients with PMGCTs and hematologic neoplasms. The PMGCT was composed mostly of yolk sac tumor whereas the hematologic neoplasms had morphologic features that resembled CMML and HLH. The hematologic neoplasms from both patients harbored isochromosome 12p [i(12p)] and TP53 mutations, supporting a clonal relationship between these tumors. This association represents a unique clinical syndrome that likely contributes to the poor clinical outcome of these patients.

Quantitative Off-Target Detection of Epstein-Barr Virus-Derived DNA in Routine Molecular Profiling of Hematopoietic Neoplasms by Panel-Based Hybrid-Capture Next-Generation Sequencing.

Epstein-Barr virus (EBV) is associated with hematologic and solid tumors. We utilized a hybridization capture-based next-generation sequencing (NGS) platform targeting 400 genes associated with hematological malignancies to detect and quantify nontargeted viral-derived EBV reads that aligned to the EBV reference contig (NC_007605). We evaluated 5234 samples from 3636 unique patients with hematological neoplasms and found that 100 samples (1.9%) in 93 unique patients had ≥6 EBV reads (range, 6 to 32,325; mean, 827.5; median, 54). Most (n = 73, 73%) represented known EBV-associated conditions, and the most common was post-transplant lymphoproliferative disorders (n = 21, 29%). Documented EBV viremia was found in 4 of 27 samples with a moderate quantity of EBV reads and conditions not known to be EBV associated, whereas suspected viremia or low-level activation was likely in the remaining 23 samples. A good correlation (Spearman r = 0.8; 95% CI, 0.74-0.85) was found between EBV reads by NGS and systematic semiquantitative EBV-encoded RNA in situ hybridization in 162 available samples, particularly at greater EBV involvement. An optimal threshold for significant morphologic EBV involvement was found to be ≥10 reads by the receiver operating characteristic analysis (area under the curve, 0.990; 95% CI, 0.9974%-1.000%). Thus, in addition to mutational analysis, hybrid-capture-based NGS panels can detect and quantitate off-target EBV-derived viral DNA, which correlates well with morphology.

The Impact of Mutation of Myelodysplasia-Related Genes in De Novo Acute Myeloid Leukemia Carrying NPM1 Mutation.

Background: The impact of gene mutations typically associated with myelodysplastic syndrome (MDS) in acute myeloid leukemia (AML) with NPM1 mutation is unclear. Methods: Using a cohort of 107 patients with NPM1-mutated AML treated with risk-adapted therapy, we compared survival outcomes of patients without MDS-related gene mutations (group A) with those carrying concurrent FLT3-ITD (group B) or with MDS-related gene mutations (group C). Minimal measurable disease (MMD) status assessed by multiparameter flow cytometry (MFC), polymerase chain reaction (PCR), and/or next-generation sequencing (NGS) were reviewed. Results: Among the 69 patients treated intensively, group C showed significantly inferior progression-free survival (PFS, p < 0.0001) but not overall survival (OS, p = 0.055) compared to group A. Though groups A and C had a similar MMD rate, group C patients had a higher relapse rate (p = 0.016). Relapse correlated with MMD status at the end of cycle 2 induction (p = 0.023). Survival of group C patients was similar to that of group B. Conclusion: MDS-related gene mutations are associated with an inferior survival in NPM1-mutated AML.

CBFB Break-Apart FISH Testing: An Analysis of 1629 AML Cases with a Focus on Atypical Findings and Their Implications in Clinical Diagnosis and Management.

Fluorescence in situ hybridization (FISH) is a confirmatory test to establish a diagnosis of inv(16)/t(16;16) AML. However, incidental findings and their clinical diagnostic implication have not been systemically studied. We studied 1629 CBFB FISH cases performed in our institution, 262 (16.1%), 1234 (75.7%), and 133 (8.2%) were reported as positive, normal, and abnormal, respectively. The last included CBFB copy number changes (n = 120) and atypical findings such as 3'CBFB deletion (n = 11), 5'CBFB deletion (n = 1), and 5'CBFB gain (n = 1). Correlating with CBFB-MYH11 RT-PCR results, totally 271 CBFB rearrangement cases were identified, including five with discrepancies between FISH and RT-PCR due to new partner genes (n = 3), insertion (n = 1), or rare CBFB-MYH11 variant (n = 1) and eight with 3'CBFB deletion. All cases with atypical findings and/or discrepancies presented clinical diagnostic challenges. Correlating FISH signal patterns and karyotypes, additional chromosome 16 aberrations (AC16As) show impacts on the re-definition of a complex karyotype and prognostic prediction. The CBFB rearrangement but not all AC16As will be detected by NGS-based methods. Therefore, FISH testing is currently still needed to provide a quick and straightforward confirmatory inv(16)/t(16;16) AML diagnosis and additional information related to clinical management.

Aggressive Mediastinal Lymphomas.

The mediastinum contains essentially all major intrathoracic organs except for the lungs. A variety of both benign and malignant tumors can involve the mediastinum, of which lymphoma is the most common malignancy. Compared to secondary mediastinal involvement by systemic lymphomas, primary mediastinal lymphomas are less common with several specific entities that are mainly confined to mediastinal lymph nodes, and/or thymus. This review will summarize the clinical, histologic, immunophenotypic and molecular genetic features of the most common and most aggressive primary mediastinal lymphomas as well as provide suggested immunohistochemistry panels and differential diagnoses.

Incidental identification of inv(16)(p13.1q22)/CBFB-MYH11 variant transcript in a patient with therapy-related acute myeloid leukemia by routine leukemia translocation panel screen: implications for diagnosis and therapy.

A 52-yr-old woman presented with therapy-related acute myeloid leukemia. A bone marrow biopsy showed 21% blasts with a myeloid phenotype and no other notable features such as abnormal eosinophils. Routine nanofluidics-based reverse transcriptase polymerase chain reaction (PCR) leukemia translocation panel designed to screen for recurrent genetic abnormalities in acute leukemia detected an inversion 16 transcript variant E. This prompted rereview of karyotype and fluorescence in situ hybridization studies, which confirmed inv(16), leading to appropriate prognostication and modification of treatment. This case underscores the utility of a powerful molecular screening method for the routine detection of recurrent genetic abnormalities of acute myeloid leukemia. It was especially useful in this case because of the lack of characteristic morphologic findings seen in inversion 16 and the difficulty in its detection by conventional karyotype analysis.

Myeloid/lymphoid neoplasms with FLT3 rearrangement.

Myeloid/lymphoid neoplasms (M/LN) with 13q12/FLT3 rearrangement have been suggested as candidates for possible inclusion in the World Health Organization classification group of M/LN with eosinophilia (M/LN-eo). We report 12 patients with confirmed FLT3 rearrangement, six with t(12;13)/ETV6-FLT3; one with ins(13;22)/BCR-FLT3; and five with an unconfirmed partner gene located on chromosome bands 2p16, 3q27, 5q15, 5q35, and 7q36. Disease presentations were heterogeneous, including lymphoblastic leukemia/lymphoma, myeloid sarcoma, chronic eosinophilic leukemia, chronic myelomonocytic leukemia, and myelodysplastic syndrome. However, some common features were observed, such as extramedullary involvement (n = 7, 58%), associated eosinophilia in blood, bone marrow, or tissue (n = 8, 67%), multilineage involvement, either as biphasic myeloid/lymphoid neoplasms (n = 2) or mixed phenotype acute leukemia (n = 2). Mutations were detected in 4/8 (50%) patients by next-generation sequencing. None (0/10) had FLT3 or KIT mutations. Eleven patients received disease-based chemotherapy or hypomethylating agents, three received FLT3 inhibitors, and five patients proceeded to hematopoietic stem cell transplant. Together with a review of 16 cases published in the literature, it is apparent that M/LNs with FLT3 rearrangement show disease features reminiscent of members in the category of M/LN-eo with PDGFRA, PDGFRB, FGFR1, and PCM1/JAK2 rearrangement, characterized by a specific gene rearrangement, frequent eosinophilia, multi-lineage involvement and therapeutic benefit from kinase inhibitors.

Next generation sequencing of breast implant-associated anaplastic large cell lymphomas reveals a novel STAT3-JAK2 fusion among other activating genetic alterations within the JAK-STAT pathway.

Breast implant associated anaplastic large cell lymphoma (BIA-ALCL) is a distinct type of ALCL, and a new provisional entity by the 2016 revision of the World Health Organization (WHO) classification of tumors of hematopoietic and lymphoid tissues. In contrast to systemic and primary cutaneous ALCLs, BIA-ALCLs have been genetically characterized by the absence of fusions and frequent activation of the JAK-STAT3 pathway through mutations in JAK1 and STAT3. In this study, we report the results of the genetic profiling of 9 BIA-ALCL cases supporting the role of the JAK-STAT pathway activation in this entity, including the identification of an activating STAT3-JAK2 fusion similar to those recently reported in T-cell lymphoproliferative disorders of the gastrointestinal tract. To our knowledge, this is the first fusion reported in BIA-ALCL, providing further insight into the overall genetic landscape of this rare entity as well as uncovering potential options for targeted therapy in cases with advanced disease.