The 5th edition of the World Health Organization Classification of Haematolymphoid Tumours: Lymphoid Neoplasms.

We herein present an overview of the upcoming 5th edition of the World Health Organization Classification of Haematolymphoid Tumours focussing on lymphoid neoplasms. Myeloid and histiocytic neoplasms will be presented in a separate accompanying article. Besides listing the entities of the classification, we highlight and explain changes from the revised 4th edition. These include reorganization of entities by a hierarchical system as is adopted throughout the 5th edition of the WHO classification of tumours of all organ systems, modification of nomenclature for some entities, revision of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities, as well as inclusion of tumour-like lesions, mesenchymal lesions specific to lymph node and spleen, and germline predisposition syndromes associated with the lymphoid neoplasms.

Patch/plaque mycosis-fungoides-like presentations of DUSP22-translocated T-cell lymphomas.

The DUSP22-IRF4 gene rearrangement results in downregulation of DUSP22, a presumed tumor suppressor in T-cell lymphomagenesis. It has been described in some cases of primary cutaneous and systemic anaplastic large-cell lymphoma, lymphomatoid papulosis, and transformed mycosis fungoides. Here we describe two patients with clinical lesions resembling patch/plaque mycosis fungoides that did not meet WHO criteria for large-cell transformation on histopathology yet showed a DUSP22 translocation. One patient who had a history of systemic anaplastic large-cell lymphoma with DUSP22 translocation presented with cutaneous involvement by his systemic lymphoma along with lymphomatoid papulosis and mycosis-fungoides-like lesions, all showing an identical immunophenotype and T-cell clone. These cases expand the spectrum of DUSP22-rearranged lymphomas to include mycosis-fungoides-like presentations without large-cell transformation.

Hybrid chemotherapy regimen (FLAG-IDA-vincristine-prednisone) for acute leukemia with mixed-phenotype blasts.

BACKGROUND: Acute leukemia with mixed-phenotype blasts is associated with poor outcomes. There are no standard treatment regimens. Due to disease heterogeneity, controversy exists over whether an AML-based, ALL-based, or a combined (hybrid) AML/ALL-based regimen is most appropriate. MATERIALS AND METHODS: We conducted a single-center, retrospective case series review of patients with acute leukemia with mixed phenotype blasts as described by the European Group for Immunological Characterization of Leukemia (EGIL) or the 2008 WHO classification. Patients were treated from November 2014 and December 2019 with the combination chemotherapy regimen FLAG-idarubicin-vincristine-prednisone with or without rituximab. Outcomes included induction response, time to transplant, time to relapse, overall survival, time to neutrophil or platelet recovery, infection, and duration of hospitalization. RESULTS: The median age was 68 years (range 21-77). Six patients (87.5 %) had unfavorable/complex cytogenetics. All patients achieved a complete remission (CR) or complete remission with incomplete hematologic recovery (CRi). Estimated 1-year overall survival was 85.7 %. There were no deaths during induction, with a 22 day median duration of hospitalization for induction. CONCLUSION: The combination of FLAG, idarubicin, vincristine, and prednisone (FLAG-VIPR) demonstrated favorable induction responses in a disease state with historically poor outcomes and should be studied in a prospective clinical trial.

Diagnostic Considerations in the Evaluation of Large B-Cells on Lymph Node Cytology Specimens.

Fine needle aspiration (FNA) has become increasingly popular in the evaluation of lymph nodes for lymphoproliferative disorders, but there are limitations to accurate subclassification of lymphoma using morphology alone. This case aims to expand diagnostic considerations of large B-cell populations identified on FNA material. We also address the significance of Epstein-Barr virus (EBV) DNA in the workup of patients with suspected lymphoma by FNA.

Cutaneous follicle center lymphomas with plasmacytic differentiation.

Follicle center lymphomas, including primary cutaneous follicle center lymphoma (PCFCL), may rarely show plasmacytic differentiation. Such cases can pose a diagnostic challenge and can be mistaken for other lymphomas that more commonly include plasma cells. Here, we report four cases of PCFCL and one case of systemic follicular lymphoma involving the skin with associated monotypic plasma cells, including the clinical, morphologic and immunophenotypic features.

Renal Clearable Gold Nanoparticle-Functionalized Silk Film for in vivo Fluorescent Temperature Mapping.

Implantable optical sensing devices that can continuously monitor physiological temperature changes hold great potential toward applications in healthcare and medical field. Here, we present a conceptual foundation for the design of biocompatible temperature sensing device by integrating renal clearable luminescent gold nanoparticles (AuNPs) with silk film (AuNPs-SF). We found that the AuNPs display strong temperature dependence in both near-IR fluorescence intensity and lifetime over a large temperature range (10-60°C), with a fluorescence intensity sensitivity of 1.72%/°C and lifetime sensitivity of 0.09 µs/°C. When integrated, the AuNPs with biocompatible silk film are implanted in the dorsal region of mice. The fluorescence imaging of the AuNPs-SF in the body shows a linear relationship between the average fluorescence intensity and temperature. More importantly, <3.68% ID gold are left in the body, and no adverse effect is observed for 8 weeks. This AuNPs-SF can be potentially used as a flexible, biocompatible, and implantable sensing device for in vivo temperature mapping.

Primary Cutaneous Composite Lymphomas.

Composite lymphomas have been defined as 2 distinct subtypes of lymphoma occurring at a single anatomic site. Composite lymphomas limited to the skin are a rare occurrence and pose a unique challenge. Many reported cases within the skin are combined B-cell and T-cell lymphomas, typically mycosis fungoides and a low-grade B-cell lymphoma. These cases are challenging to recognize because lymphoid infiltrates within the skin often include a mixed population of B cells and T cells. In particular, reactive lymphoid proliferations (pseudolymphomas), primary cutaneous low-grade B-cell lymphomas, and primary cutaneous CD4+ T-cell lymphoproliferative disorder may show nearly equal numbers of B cells and T cells. In order to exclude these possibilities, overwhelming evidence in support of each lymphoma is helpful, including abnormal architecture, cytology, and immunophenotype, as well as molecular genetic evidence of clonality.

Mixed-Phenotype Acute Leukemia: Diagnostic Criteria and Pitfalls.

Mixed-phenotype acute leukemia (MPAL) is a heterogeneous category in the World Health Organization classification that comprises acute leukemias with discrete admixed populations of myeloid and lymphoid blasts ("bilineal") or with extensive coexpression of lymphoid and myeloid markers in a single blast population ("biphenotypic"). Flow cytometric findings suggestive of MPAL are often met with consternation by pathologists and oncologists alike, owing to unfamiliarity with the disease and uncertainty about how MPAL fits into established paradigms for treatment of acute leukemia. The purpose of this review is to explain the diagnostic criteria for MPAL, summarize its biological and clinical features, and address common diagnostic pitfalls of these unusual leukemias.

Fibrin-associated EBV-positive Large B-Cell Lymphoma: An Indolent Neoplasm With Features Distinct From Diffuse Large B-Cell Lymphoma Associated With Chronic Inflammation.

Incidental cases of localized fibrin-associated Epstein-Barr virus (EBV)+ large B-cell proliferations have been described at unusual anatomic sites and have been included in the category of diffuse large B-cell lymphoma associated with chronic inflammation (DLBCL-CI) in the WHO Classification. We describe 12 cases and review the literature to define their clinicopathologic spectrum and compare features with typical cases of DLBCL-CI. Median age was 55.5 years with a M:F ratio of 3. In all 12 cases, the lymphoma was an incidental microscopic finding involving atrial myxomas (n=3), thrombi associated with endovascular grafts (n=3), chronic hematomas (n=2), and pseudocysts (n=4). All cases tested were nongerminal center B-cell origin, type III EBV latency, and were negative for MYC rearrangements and alternative lengthening of telomeres by FISH. Most showed high CD30, Ki67, and PD-L1, and low to moderate MYC and p53 expression. Among 11 patients with detailed follow-up, 6 were treated surgically, 3 with cardiac or vascular lesions had persistent/recurrent disease at intravascular sites, and 4 died of causes not directly attributable to lymphoma. Reports of previously published fibrin-associated cases showed similar features, whereas traditional DLBCL-CI cases with a mass lesion had significantly higher lymphoma-associated mortality. Fibrin-associated EBV+ large B-cell lymphoma is clinicopathologically distinct from DLBCL-CI, warranting separate classification. Most cases, particularly those associated with pseudocysts, behave indolently with the potential for cure by surgery alone and may represent a form of EBV+ lymphoproliferative disease rather than lymphoma. However, primary cardiac or vascular disease may have a higher risk of recurrence despite systemic chemotherapy.

Blood and Bone Marrow Evaluation for Eosinophilia.

Evaluation of peripheral blood and bone marrow for an indication of persistent eosinophilia can be a challenging task because there are many causes of eosinophilia and the morphologic differences between reactive and neoplastic causes are often subtle or lack specificity. The purpose of this review is to provide an overview of the differential diagnosis for eosinophilia, to recommend specific steps for the pathologist evaluating blood and bone marrow, and to emphasize 2 important causes of eosinophilia that require specific ancillary tests for diagnosis: myeloproliferative neoplasm with PDGFRA rearrangement and lymphocyte-variant hypereosinophilic syndrome.

The immunophenotypic spectrum of primary mediastinal large B-cell lymphoma reveals prognostic biomarkers associated with outcome.

Primary mediastinal large B-cell lymphoma (PMBL) is a distinct subtype of diffuse large B-cell lymphoma (DLBCL) that shows overlap with classical Hodgkin lymphoma (CHL) and a favorable prognosis compared to mediastinal gray-zone lymphoma (MGZL). We performed immunohistochemistry on initial diagnostic specimens of 49 cases of uniformly treated PMBL to determine the frequency and clinical significance of expression of antigens commonly seen in CHL and MGZL, along with markers previously shown to be prognostic in DLBCL, not otherwise specified. The median age was 37 years with a female:male ratio of 2.3. After a median follow-up of 78 months, 24% of patients had relapsed or refractory disease and 22% had died; the 5-year PFS was 70%. Variable CD15 expression was seen in 31% of cases, but was not associated with adverse outcome. Hans cell-of-origin, proliferation index, and MYC/BCL2 coexpression were not associated with outcome, while low PDL1 (P = 0.011) and high MUM1 (P = 0.065) staining were each associated with shorter PFS. A biologic risk score (one point each for low PDL1 and high MUM1) stratified patients into three prognostic risk groups for PFS (P = 0.001) and OS (P = 0.032). On separate multivariate models, low PDL1 was independent of R-IPI risk group for PFS (HR 6.0, P = 0.023), as was a biologic risk score of 2 (HR 5.6, P = 0.011). Incorporation of the biologic risk score sub-stratified patients within R-IPI groups for both PFS (P < 0.001) and OS (P < 0.001). In summary, we characterize the immunophenotypic spectrum of PMBL and identify PDL1 and MUM1 as prognostic biomarkers for high-risk disease. Am. J. Hematol. 91:E436-E441, 2016. © 2016 Wiley Periodicals, Inc.

Peripheral T-cell lymphomas with cytotoxic phenotype in patients with chronic lymphocytic leukemia/small lymphocytic lymphoma.

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is relatively common, and patients occasionally develop other neoplasms; however, patients who develop other types of lymphomas are rare. We encountered 3 patients with CLL/SLL (one 59-y-old man and 2 women aged 56 and 66 y) who developed T-cell lymphomas. Both women developed ALK anaplastic large cell lymphomas (ALCLs), whereas the man developed CD8 peripheral T-cell lymphoma, not otherwise specified. All 3 T-cell lymphomas expressed granzyme B and perforin, indicating a cytotoxic immunophenotype. In 1 case, the first presentation was a lymph nodal composite lymphoma. In the other 2 cases, the T-cell lymphomas arose <1 year after the diagnosis of CLL/SLL and were identified in a lymph node in one case and in the spleen in the other. The patient with a composite lymphoma (SLL/ALK ALCL) was treated and was free of disease at last follow-up, whereas the other 2 patients succumbed to their disease, 1 month and 7 months after the diagnosis of T-cell lymphoma. Peripheral T-cell lymphomas rarely occur in CLL/SLL patients. On the basis of our small series, those with a cytotoxic phenotype appear to be more common in this setting. The occurrence of ALK ALCL in 2 older patients was especially surprising and suggested that CLL/SLL may have played a role in the development of ALCL.

Spatiotemporal patterns of multipotentiality in Ptf1a-expressing cells during pancreas organogenesis and injury-induced facultative restoration.

Pancreatic multipotent progenitor cells (MPCs) produce acinar, endocrine and duct cells during organogenesis, but their existence and location in the mature organ remain contentious. We used inducible lineage-tracing from the MPC-instructive gene Ptf1a to define systematically in mice the switch of Ptf1a(+) MPCs to unipotent proacinar competence during the secondary transition, their rapid decline during organogenesis, and absence from the mature organ. Between E11.5 and E15.5, we describe tip epithelium heterogeneity, suggesting that putative Ptf1a(+)Sox9(+)Hnf1ß(+) MPCs are intermingled with Ptf1a(HI)Sox9(LO) proacinar progenitors. In the adult, pancreatic duct ligation (PDL) caused facultative reactivation of multipotency factors (Sox9 and Hnf1ß) in Ptf1a(+) acini, which undergo rapid reprogramming to duct cells and longer-term reprogramming to endocrine cells, including insulin(+) ß-cells that are mature by the criteria of producing Pdx1(HI), Nkx6.1(+) and MafA(+). These Ptf1a lineage-derived endocrine/ß-cells are likely formed via Ck19(+)/Hnf1ß(+)/Sox9(+) ductal and Ngn3(+) endocrine progenitor intermediates. Acinar to endocrine/ß-cell transdifferentiation was enhanced by combining PDL with pharmacological elimination of pre-existing ß-cells. Thus, we show that acinar cells, without exogenously introduced factors, can regain aspects of embryonic multipotentiality under injury, and convert into mature ß-cells.

Context-specific α- to-ß-cell reprogramming by forced Pdx1 expression.

Using single transcription factors to reprogram cells could produce important insights into the epigenetic mechanisms that direct normal differentiation, or counter inappropriate plasticity, or even provide new ways of manipulating normal ontogeny in vitro to control lineage diversification and differentiation. We enforced Pdx1 expression from the Neurogenin-3-expressing endocrine commitment point onward and found during the embryonic period a minor increased ß-cell allocation with accompanying reduced α-cell numbers. More surprisingly, almost all remaining Pdx1-containing glucagon/Arx-producing cells underwent a fairly rapid conversion at postnatal stages, through glucagon-insulin double positivity, to a state indistinguishable from normal ß cells, resulting in complete α-cell absence. This α-to-ß conversion was not caused by activating Pdx1 in the later glucagon-expressing state. Our findings reveal that Pdx1 can work single-handedly as a potent context-dependent autonomous reprogramming agent, and suggest a postnatal differentiation evaluation stage involved in normal endocrine maturation.