Cranial Fasciitis in Children: Expanding the Spectrum of USP6-Associated Clonal Transient Neoplasms.

Background: Cranial fasciitis (CF) is a benign (myo)fibroblastic proliferation of children. Typical presentation consists of a rapidly growing solitary mass on the temporal or parietal cranium in the first 2 years of age. CF is characterized by a rapid growth followed by a relative slowdown and even growth arrest. The finding of somatic USP6 gene rearrangements demonstrating clonality in CF together with its clinical behavior places it in the category of diseases recently termed "transient neoplasia."Methods: Histological, immunohistochemical, and molecular findings of 18 patients with CF were retrospectively studied.Results: The tumor typically presented as a painless rapidly enlarging mass in the temporal region. Sixty-six percent of the cases harbored USP6 gene rearrangement. Nine patients were treated with gross total resection (GTR) and 9 with subtotal tumor resection (STR). Two patients treated with GTR had recurrence. Five patients treated with STR had progression-free disease for at least 10 months after surgery and in four patients the tumor regressed spontaneously a median 16 months after surgery.Conclusions: In this largest series to date, we reported the clinicopathological, immunohistochemical, and molecular findings of 18 pediatric cases of CF with emphasis on the clinical growth pattern of these tumors.

Myelodysplastic syndrome/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis: Ringing in a new future.

Myelodysplastic syndrome/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis (MDS/MPN-RS-T) is a rare hematologic malignancy belonging to the category of myelodysplastic syndrome (MDS)/myeloproliferative neoplasm (MPN) overlap syndromes. While certain clinical features, including anemia and thrombocytosis, are common to both the MDS and MPN disease components, the biologic consequences of the spliceosome mutation SF3B1 results in notable clinical exceptions. Importantly, both overall and leukemia free survival are shorter for MDS/MPN-RS-T when compared to essential thrombocythemia (ET). In the case of MDS/MPN-RS-T, thrombotic risk is not associated with the presence of JAK2V617F, nor history of prior thrombosis, but is associated with the presence of the mutated spliceosome gene SF3B1. In this review, we highlight the biology, pathology, risk stratification, and treatment approach to MDS/MPN-RS-T. In particular, we focus on clinical management concepts, which are largely borrowed from MDS and MPN, including the use of cytoreduction, bone marrow stimulating agents, and the role of allogeneic stem cell transplantation. We end by highlighting unmet needs and future research priorities in MDS/MPN-RS-T.

Unexpected pancytopenia: Dasatinib induced aplastic anemia in chronic myeloid leukemia.

INTRODUCTION: The use of TKIs in CML has dramatically altered the natural course of the disease and improved outcomes for patients. TKIs overall have a very favorable safety profile. Dasatinib, a second generation TKI, is commonly used as a first-line treatment option in CML. CASE REPORT: We describe the first two reported cases of first-line dasatinib induced aplastic anemia in CML. In both patients, pancytopenia occurred within one year of diagnosis/starting dasatinib. Both bone marrow biopsies showed hypocellularity with mild fibrosis and persistent BCR-Abl1 positivity. MANAGEMENT & OUTCOME: Dose reduction was attempted without success in both patients. In one patient, multiple TKIs were trialed, while in the other, growth factor support was attempted; neither regimen was effective. Ultimately, the cytopenias associated with dasatinib were only resolved after immunosuppression in one patient and allogeneic stem cell transplant in the other patient. DISCUSSION: Prior reports have shown that aplasia/aplastic anemia can rarely be associated with imatinib and nilotinib. Here we show that dasatinib can lead to this phenomenon as well. This diagnosis should be considered in patients with CML who unexpectedly develop cytopenias.

PD-1 inhibition in advanced myeloproliferative neoplasms.

Myelofibrosis (MF) is a clonal stem cell neoplasm characterized by abnormal JAK-STAT signaling, chronic inflammation, cytopenias, and risk of transformation to acute leukemia. Despite improvements in the therapeutic options for patients with MF, allogeneic hematopoietic stem cell transplantation remains the only curative treatment. We previously demonstrated multiple immunosuppressive mechanisms in patients with MF, including increased expression of programmed cell death protein 1 (PD-1) on T cells compared with healthy controls. Therefore, we conducted a multicenter, open-label, phase 2, single-arm study of pembrolizumab in patients with Dynamic International Prognostic Scoring System category of intermediate-2 or greater primary, post-essential thrombocythemia or post-polycythemia vera myelofibrosis that were ineligible for or were previously treated with ruxolitinib. The study followed a Simon 2-stage design and enrolled a total of 10 patients, 5 of whom had JAK2V617mutation, 2 had CALR mutation, and 6 had additional mutations. Most patients were previously treated with ruxolitinib. Pembrolizumab treatment was well tolerated, but there were no objective clinical responses, so the study closed after the first stage was completed. However, immune profiling by flow cytometry, T-cell receptor sequencing, and plasma proteomics demonstrated changes in the immune milieu of patients, which suggested improved T-cell responses that can potentially favor antitumor immunity. The fact that these changes were not reflected in a clinical response strongly suggests that combination immunotherapeutic approaches rather than monotherapy may be necessary to reverse the multifactorial mechanisms of immune suppression in myeloproliferative neoplasms. This trial was registered at www.clinicaltrials.gov as #NCT03065400.

Contemporary Risk Stratification and Treatment of Chronic Myelomonocytic Leukemia.

Chronic myelomonocytic leukemia (CMML) is a hematologic malignancy characterized by absolute monocytosis, one or more lineage dysplasia, and proliferative features including myeloid hyperplasia, splenomegaly, and constitutional symptoms. Because of vast clinical heterogeneity in presentation and course, risk stratification is used for a risk-adapted treatment strategy. Numerous prognostic scoring systems exist, some of which incorporate mutational information. Treatment ranges from observation to allogeneic hematopoietic stem cell transplantation. Therapies include hydroxyurea for cytoreduction, hypomethylating agents, and the JAK1/2 inhibitor ruxolitinib to address splenomegaly and constitutional symptoms. Recently, oral decitabine with cedazuridine was approved and represents a convenient treatment option for CMML patients. Although novel therapeutics are in development for CMML, further work is needed to elucidate possible targets unique to the CMML clone. In this review, we will detail the pathophysiology, risk stratification, available treatment modalities, and novel therapies for CMML, and propose a modern treatment algorithm. IMPLICATIONS FOR PRACTICE: Chronic myelomonocytic leukemia (CMML) is a clinically heterogenous disease, which poses significant management challenges. The diagnosis of CMML requires bone marrow biopsy and aspirate with thorough evaluation. Risk stratification and symptom assessment are essential to designing an effective treatment plan, which may include hypomethylating agents (HMAs) in intermediate or high-risk patients. The recently approved oral decitabine/cedazuridine provides a convenient alternative to parenteral HMAs. Ruxolitinib may be effective in ameliorating proliferative symptoms and splenomegaly. Allogeneic stem cell transplantation remains the only treatment with curative potential; however, novel therapies are in clinical development which may significantly alter the therapeutic landscape of CMML.

Safety and Efficacy: Clinical Experience of Venetoclax in Combination With Hypomethylating Agents in Both Newly Diagnosed and Relapsed/Refractory Advanced Myeloid Malignancies.

Hypomethylating agents (HMAs) in combination with venetoclax have been widely adopted as the standard of care for patients who cannot tolerate induction chemotherapy and for patients who have relapsed/refractory (R/R) acute myeloid leukemia (AML). This study retrospectively analyzed the outcomes of all patients with AML (n = 65) or myelodysplastic syndrome (n = 7) who received the combination of HMA and venetoclax at our institution. Outcomes measured included complete remission (CR) and CR with incomplete hematologic recovery (CRi) rates, duration of response (DOR), and overall survival (OS). Patient mutational profiles and transfusion requirements were also assessed. Of 26 newly diagnosed AML patients, the CR/CRi rate was 53.8%. The median DOR and OS were 6.9 months and not reached, respectively. Of 39 R/R AML patients, the CR/CRi rate was 38.5%. The median DOR and OS were both 8.1 months. Responders to HMA and venetoclax were enriched for TET2, IDH1, and IDH2 mutations, while nonresponders were associated with FLT3 and RAS mutations. Adaptive resistance was observed through various mechanisms including acquired RAS pathway mutations. Of transfusion-dependent patients, 12.2% and 15.2% achieved red blood cell (RBC) and platelet transfusion independence, respectively, while 44.8% and 35.1% of RBC and platelet transfusion independent patients, respectively, became transfusion dependent. In total 59.1% of patients developed a ≥grade 3 infection and 46.5% neutropenic fever. HMA + venetoclax can lead to impressive response rates with moderately durable remissions and survival. However, the benefits of this combination are diminished by the significant toxicities from infection, persistent cytopenias, and transfusion requirements.

Findings of Hepatic Severe Acute Respiratory Syndrome Coronavirus-2 Infection.

BACKGROUND & AIMS: Liver injury due to coronavirus disease 2019 (COVID-19) is being increasingly recognized. Abnormal liver chemistry tests of varying severities occur in a majority of patients. However, there is a dearth of accompanying liver histologic studies in these patients. METHODS: The current report details the clinical courses of 2 patients having severe COVID-19 hepatitis. Liver biopsies were analyzed under light microscopy, portions of liver tissue were hybridized with a target probe to the severe acute respiratory syndrome coronavirus-2 S gene, and small sections from formalin-fixed paraffin-embedded liver tissue were processed for electron microscopy. RESULTS: The liver histology of both cases showed a mixed inflammatory infiltrate with prominent bile duct damage, endotheliitis, and many apoptotic bodies. In situ hybridization and electron microscopy suggest the intrahepatic presence of severe acute respiratory syndrome coronavirus-2, the findings of which may indicate the possibility of direct cell injury. CONCLUSIONS: On the basis of the abundant apoptosis and severe cholangiocyte injury, these histopathologic changes suggest a direct cytopathic injury. Furthermore, some of the histopathologic changes may resemble acute cellular rejection occurring after liver transplantation. These 2 cases demonstrate that severe COVID-19 hepatitis can occur even in the absence of significant involvement of other organs.

Myeloid Sarcoma of the Testis in Children: Clinicopathologic and Immunohistochemical Characteristics With KMT2A (MLL) Gene Rearrangement Correlation.

Myeloid sarcoma (MS) is defined as an extramedullary mass-forming lesion composed of immature myeloid cells. It is a rare but well-known manifestation of acute myeloid leukemia. Pediatrics testicular MS may pose a possible diagnostic challenge, an issue that is underscored in the few testicular pediatric MS cases reported in the literature. Herein, we report a series of 5 cases of pediatric testicular MS that are evaluated at the morphologic and immunohistochemical levels with correlation with the KMT2A (MLL) rearrangement status. Three patients presented with no prior history of acute myeloid leukemia. All 5 cases showed monoblastic morphology; positive for CD33, CD43, CD68, CD163, CD4 (dim), and lysozyme; and negative for CD10, CD34, CD117, and myeloperoxidase. KMT2A (MLL) rearrangement was detected in 4 of the 5 cases. In the literature, 8 more cases of pediatric testicular lymphoma were reported. Most of them showed monocytic differentiation and KMT2A (MLL) rearrangement was reported in 3 of the cases. In conclusions, testicular MS in pediatric patients shows monoblastic differentiation which may be attributed to the KMT2A (MLL) rearrangement. We also highlight the importance of using an extended immunohistochemistry panel in the diagnosis of MS.

Bone marrow morphologic features, MyPRS, and gene mutation correlations in plasma cell myeloma.

Genetics has played an important role in risk stratification for plasma cell myeloma patients, providing therapeutic guidance. In this study, we investigated the correlation of bone marrow morphologic features and genetic aberrations, including gene expression profiles, translocations, and gene mutations. For the first time we show that high plasma cell volume, diffuse sheet growth pattern, immature cell morphology, high mitotic index, and increased reticulin fibrosis, significantly correlates with high risk disease determined by MyPRS gene expression profiles. Furthermore, we show the association between MyPRS risk stratification and chromosomal alterations and specific gene mutations. We also demonstrate the combinational effect of TP53 mutation and 17p loss on the histological changes in bone marrow.

Blastic Plasmacytoid Dendritic Cell Neoplasm-Current Insights.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare clonal hematologic malignancy of plasmacytoid dendritic cell precursors. The presentation and clinical course of BPDCN is widely heterogeneous and was most recently categorized as a distinct clinical entity by the World Health Organization in 2016. The expanded understanding of the pathobiology of BPDCN has improved diagnostic accuracy and informed novel targeted therapeutic options. The United States Food and Drug Administration-approval of tagraxofusp (SL-401) in December 2018 has focused attention on this leukemia frequently associated with skin involvement. Herein, we aim to: (1) review etiology; (2) summarize diagnostic criteria; and (3) discuss historic treatments and novel therapies for BPDCN.

Acquired amegakaryocytic thrombocytopenia as a rare cause of thrombocytopenia during pregnancy.

A rare case of acquired amegakaryocytic thrombocytopenia (AATP) in a 35-year-old woman who presented with anaemia and thrombocytopenia at 22 weeks gestation. The first diagnostic impression was of an evolving aplastic anaemia; however, the patient was simultaneously diagnosed with severe vitamin B12 deficiency in the setting of vegetarianism. Once the cyanocobalamin deficiency was corrected, a repeat bone marrow biopsy revealed an isolated depletion of megakaryocytes, which suggested the diagnosis of AATP. Supportive care was provided for her anaemia and thrombocytopenia and she delivered a healthy baby girl with a normal platelet count. The patient was subsequently started on romiplostim with steady improvement in her platelet counts. This rare AATP case presentation highlights the importance of a well-structured diagnostic approach to thrombocytopenia during pregnancy and supports the successful use of thrombopoietin agonists for the management of AATP.

nCounter NanoString Assay Shows Variable Concordance With Immunohistochemistry-based Algorithms in Classifying Cases of Diffuse Large B-Cell Lymphoma According to the Cell-of-Origin.

Classifying diffuse large B-cell lymphoma (DLBCL) according to the cell-of-origin (COO) was first proposed using gene expression profiling; accordingly, DLBCL is classified into germinal-center B-cell type and activated B-cell type. Immunohistochemistry (IHC)-based classification using different algorithms is used widely due to the ability to use formalin-fixed paraffin-embedded tissue. Recently, newer techniques using RNA expression from formalin-fixed paraffin-embedded were introduced including the nCounter NanoString platform assay. In this brief report, we study the degree of concordance between the NanoString assay and 6 commonly utilized IHC-based algorithms to classify DLBCL cases by COO. Stains for CD10, BCL2, BCL6, FOXP-1, MUM-1, and LOM2 were used to classify a cohort of DLBCL by COO according to the respective IHC-algorithms. Then, RNA was extracted from the same cases for NanoString assay classification. The degree of concordance was calculated between the NanoString classification and each IHC-algorithm as well as among the different IHC-algorithm themselves. The concordance in COO classification of DLBCL between NanonoString assay and IHC-based algorithms is variable depending on the used IHC-algorithm; the highest concordance is seen with the Visco algorithm (κ=0.69; P=0.001). Therefore, discrepancies between the recently introduced NanoString assay and the commonly utilized IHC-algorithms are expected to some extent and should be taken into consideration when interpreting conflicting results.

MEF2B is a member of the BCL6 gene transcriptional complex and induces its expression in diffuse large B-cell lymphoma of the germinal center B-cell-like type.

Myocyte enhancer-binding factor 2B (MEF2B) has been implicated as a transcriptional regulator for BCL6. However, details about the interaction between MEF2B and BCL6 during expression, as well as the relationship of MEF2B to the expression of other germinal center (GC) markers, have not yet been fully explained. Using germinal center B-cell-like diffuse large B-cell lymphoma (GC-DLBCL) and activated B-cell diffuse large B-cell lymphoma (ABC-DLBCL) cell lines, we analyzed the expression of MEF2B and its associations with BCL6, CD10, and ERK. Furthermore, small interfering RNA (siRNA) was used to study the possible effects of MEF2B knockdown on these proteins and cell growth. Analysis of the BCL6 transcriptional complex was performed using electrophoretic mobility shift assay. The correlation between MEF2B expression and the genetic type of DLBCL was assessed using immunohistochemistry on 111 patient samples, and via in silico analysis of publicly available microarray (Gene Expression Omnibus (GEO)) datasets. Our results indicate that the expression of MEF2B protein is important for the growth of GC-DLBCL cells, as evidenced by MEF2B knockdown inhibition of cell growth and the subsequent suppression of BCL6, CD10, and ERK phosphorylation. Analysis of BCL6 transcription factors in nuclear extracts of MEF2-expressing DLBCL cells showed involvement of MEF2B with AP-2α and BCL6 proteins in the formation of the BCL6 gene transcriptional complex. Indeed, differential expression of MEF2B in the GC-DLBCL is statistically significant compared to the ABC-DLBCL in the GEO datasets, as well as in tissue microarray, as indicated via immunohistochemistry (Visco-Young algorithm). Our findings indicate that MEF2B is an essential component of the BCL6 gene transcriptional complex for the regulation of DLBCL growth via the promotion of BCL6 expression. Beyond its regulatory role in DLBCL growth, MEF2B expression correlated positively with BCL6 and CD10 expression, and was preferentially expressed in the GBC-DLBCL group.

Distinguishing autoimmune myelofibrosis from primary myelofibrosis.

Bone marrow fibrosis (BMF) is a histologic finding in a wide range of diseases, including malignancies, endocrine disorders, autoimmune diseases, and infections. Autoimmune myelofibrosis (AIMF) is an uncommon etiology of BMF; it can be secondary to a defined autoimmune disease, or it can be primary in the absence of a clinically diagnosed autoimmune disease but the presence of serologic evidence of autoantibodies. Distinguishing between primary myelofibrosis (PMF) and non-neoplastic AIMF is of the utmost importance because the prognosis and therapeutic options are different. This distinction, however, can be complicated by overlapping findings in the 2 disease entities. Here, using the case of a patient with BMF in the setting of idiopathic thrombocytopenic purpura and autoimmune hemolytic anemia, we present a systematic approach to distinguishing between PMF and AIMF.

Strong NFκB Expression is Associated With High-grade Dysplasia in Barrett's Esophagus.

Nuclear factor kappa B (NFκB) is a transcription factor that regulates the activation of genes involved in proinflammatory response and growth. In this study, we utilized immunohistochemical stains for 2 of the NFκB molecules (RELA and NFκB-1) to evaluate the expression of NFκB in Barrett's esophagus (BE). Forty-three cases of BE [17 cases with no dysplasia, 16 cases with low-grade dysplasia (LGD), and 10 cases with high-grade dysplasia (HGD)], 10 normal esophageal biopsies, and 9 cases of esophageal adenocarcinoma were evaluated. Expression of NFκB-1 and RELA did not occur in normal esophageal squamous mucosa. BE without dysplasia showed weak expression of RELA and NFκB-1 in 35% and 65% of cases, respectively. BE with LGD showed weak expression of RELA and NFκB-1 in 50% and 75% of cases, respectively. Strong expression of RELA and NFκB-1 did not occur in BE without dysplasia or with LGD. BE with HGD showed strong expression of RELA and NFκB-1 in 80% and 90% of cases, respectively. All cases of adenocarcinoma showed strong expression of both RELA and NFκB-1. There was a progressive increase in staining intensity of RELA and NFκB-1 along the metaplasia-dysplasia-adenocarcinoma pathway. Strong expression of NFκB is associated with HGD and adenocarcinoma (P<0.0001). We showed that strong expression of NFκB-1 and RELA correlates highly with BE with HGD and adenocarcinoma.

Multifocal Supra and Infratentorial Medulloblastoma in an Adult: Histologic, Immunohistochemical, and Molecular Evaluation of a Rare Case and Review of the Literature.

Multifocal medulloblastomas (MMBs) in adults are exceedingly rare with only 5 reported cases to date. Medulloblastoma in adult differ from its childhood counterpart by being more often lateral in location, desmoplastic in morphology, and better in clinical prognosis. Little is known, however, about the characteristic features of MMB. This is particularly true for their molecular profiles. To date, molecular characteristics of multifocal medulloblastoma have been reported only once. Here, we present the second case of multifocal medulloblastoma along with its detailed morphology, imaging features, and molecular profiles with a critical review of the literature. We believe that MMB should be reported in detail to better understand their behavior, characterize their molecular profiles, and establish therapeutic protocols.

Interferon gamma-induced apoptosis of head and neck squamous cell carcinoma is connected to indoleamine-2,3-dioxygenase via mitochondrial and ER stress-associated pathways.

BACKGROUND: Tumor response to immunotherapy is the consequence of a concerted crosstalk between cytokines and effector cells. Interferon gamma (IFNγ) is one of the common cytokines coordinating tumor immune response and the associated biological consequences. Although the role of IFNγ in the modulation of tumor immunity has been widely documented, the mechanisms regulating IFNγ-induced cell death, during the course of immune therapy, is not described in detail. RESULTS: IFNγ triggered apoptosis of CLS-354 and RPMI 2650 cells, enhanced the protein expression and activation of indoleamine 2,3-dioxygenase (IDO), and suppressed the basal expression of heme oxygenase-1(HO-1). Interestingly, IFNγ induced the loss of mitochondrial membrane potential (Δψm) and increased accumulation of reactive oxygen species (ROS). The cytokine also induced the activation of Janus kinase (JAK)/Signal Transducer and Activator of Transcription (STAT)1, apoptosis signal-regulating kinase 1 (ASK1), p38, c-jun-N-terminal kinase (JNK) and NF-κB pathways and the transcription factors STAT1, interferon regulatory factor 1 (IRF1), AP-1, ATF-2, NF-κB and p53, and expression of Noxa protein. Furthermore, IFNγ was found to trigger endoplasmic reticulum (ER) stress as evidenced by the cleavage of caspase-4 and activation of protein kinase RNA-like endoplasmic reticulum kinase (PERK) and inositol-requiring-1α (IRE1α) pathways. Using specific inhibitors, we identified a potential role for IDO as apoptotic mediator in the regulation of IFNγ-induced apoptosis of head and neck squamous cell carcinoma (HNSCC) cells via Noxa-mediated mitochondrial dysregulation and ER stress. CONCLUSION: In addition to the elucidation of the role of IDO in the modulation of apoptosis, our study provides new insights into the molecular mechanisms of IFNγ-induced apoptosis of HNSCC cells during the course of immune therapy.

Cancer stem cell as therapeutic target for melanoma treatment.

Human malignant melanoma is a highly aggressive skin tumor that is characterized by its extraordinary heterogeneity, propensity for dissemination to distant organs and resistance to cytotoxic agents. Although chemo- and immune-based therapies have been evaluated in clinical trials, most of these therapeutics do not show significant benefit for patients with advanced disease. Treatment failure in melanoma patients is attributed mainly to the development of tumor heterogeneity resulting from the formation of genetically divergent subpopulations. These subpopulations are composed of cancer stem-like cells (CSCs) as a small fraction and non-cancer stem cells that form the majority of the tumor mass. In recent years, CSCs gained more attention and suggested as valuable experimental model system for tumor study. In melanoma, intratumoral heterogeneity, progression and drug resistance result from the unique characteristics of melanoma stem cells (MSCs). These MSCs are characterized by their distinct protein signature and tumor growth-driving pathways, whose activation is mediated by driver mutation-dependent signal. The molecular features of MSCs are either in a causal or consequential relationship to melanoma progression, drug resistance and relapse. Here, we review the current scientific evidence that supports CSC hypothesis and the validity of MSCs-dependent pathways and their key molecules as potential therapeutic target for melanoma treatment.