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We report a case of mycosis fungoides (MF) in an 18-year-old man whose neoplastic T cells expressed CD4, CD8, and CD56, with no evidence of TCR-delta or Epstein-Barr virus (EBER) expression. Clinically, neither hypopigmentation nor hyperpigmentation nor poikilodermatous skin lesions were present, and the lesions subsided with oral corticoids and retinoids and environmental solar ultraviolet exposure. Our case represents the oldest patient reported so far with nonpoikilodermatous, CD8/CD56 MF and adds to the phenotypic diversity of MF in the pediatric population. This distinct phenotype does not seem to be linked to a more aggressive course than the classic CD-4 positive one.

Skin manifestations in the context of underlying hematological malignancies are well known and not an infrequent clinical finding. They can represent specific neoplastic infiltrates or be considered as reactive. In the latter group, where granulomatous dermatitis is included, controversy has emerged recently. According to newly reported data, the histiocytes comprising these granulomata can carry the same molecular alterations found in the primary process. Moreover, the skin manifestations in these patients are sometimes the initial clue for the diagnosis of the underlying malignancy. We present here 2 cases with granulomatous skin infiltrates preceding the diagnosis of myelodysplastic/myeloproliferative neoplasms. In one of them, the same IDH2 mutation was detected in granulomatous lesions on the skin and in the bone marrow. This was performed by pyrosequencing instead of next-generation sequencing, with improved cost-effectiveness.

Supplementary Data from Tiling Path Genomic Profiling of Grade 3 Invasive Ductal Breast Cancers

Purpose: To characterize the molecular genetic profiles of grade 3 invasive ductal carcinomas of no special type using high-resolution microarray-based comparative genomic hybridization (aCGH) and to identify recurrent amplicons harboring putative therapeutic targets associated with luminal, HER-2, and basal-like tumor phenotypes.Experimental Design: Ninety-five grade 3 invasive ductal carcinomas of no special type were classified into luminal, HER-2, and basal-like subgroups using a previously validated immunohistochemical panel. Tumor samples were microdissected and subjected to aCGH using a tiling path 32K BAC array platform. Selected regions of recurrent amplification were validated by means of in situ hybridization. Expression of genes pertaining to selected amplicons was investigated using quantitative real-time PCR and gene silencing was done using previously validated short hairpin RNA constructs.Results: We show that basal-like and HER-2 tumors are characterized by “sawtooth” and “firestorm” genetic patterns, respectively, whereas luminal cancers were more heterogeneous. Apart from confirming known amplifications associated with basal-like (1q21, 10p, and 12p), luminal (8p12, 11q13, and 11q14), and HER-2 (17q12) cancers, we identified previously unreported recurrent amplifications associated with each molecular subgroup: 19q12 in basal-like, 1q32.1 in luminal, and 14q12 in HER-2 cancers. PPM1D gene amplification (17q23.2) was found in 20% and 8% of HER-2 and luminal cancers, respectively. Silencing of PPM1D by short hairpin RNA resulted in selective loss of viability in tumor cell lines harboring the 17q23.2 amplification.Conclusions: Our results show the power of aCGH analysis in unraveling the genetic profiles of specific subgroups of cancer and for the identification of novel therapeutic targets.

The transcription factors Snail, Slug, and bHLH E47 have been recently described as direct repressors of E-cadherin and inducers of epithelial-mesenchymal transition (EMT) and invasion when overexpressed in epithelial cells. Although a role of those factors in tumor progression and invasion has been proposed, whether the different repressors play distinct or redundant roles in the tumorigenic process has not been established. To further investigate this important issue, we have analyzed the gene expression profiling of Madin-Darby canine kidney (MDCK) epithelial cells expressing the different repressors (MDCK-Snail, MDCK-Slug, and MDCK-E47 cells) versus control MDCK cells by cDNA microarrays. A total of 243 clones (228 genes and 15 expressed sequence tags) were found to be differentially expressed between either of the three MDCK-derived cell lines and control MDCK cells. Twenty two of the candidate genes were validated by Northern blot, Western blot, immunofluorescence, and promoter analyses in cell lines and by immunohistochemistry in xenografted tumors. Gene clustering analysis indicated that about a third of the 243 candidate genes were common to MDCK cells expressing Snail, Slug, or E47 factors, whereas the rest of the genes were regulated in only one or two cell types. Differentially regulated genes include those related to EMT (45 genes), transcriptional regulation (18 genes), cell proliferation and signaling (54 genes), apoptosis (12 genes), and angiogenesis (9 genes). These results indicate that Snail, Slug, and E47 transcription factors induce common and specific genetic programs, supporting a differential role of the factors in tumor progression and invasion. (Cancer Res 2006; 66(19): 9543-56)

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare cytotoxic cutaneous lymphoma. Differential diagnosis with lupus erythematosus panniculitis (LEP) can be challenging and overlapping cases have been described. In this study, we investigate whether gene expression profiling may or not identify markers that can be used to improve our understanding of the disease and to make a precise differential diagnosis. SPTCL, LEP, and overlapping cases were analyzed using a customized NanoString platform including 208 genes related to T-cell differentiation, stromal signatures, oncogenes, and tumor suppressor genes. Gene expression unsupervised analysis of the samples differentiated SPTCL from LEP samples. Most overlapping cases were clustered with LEP cases. Differentially expressed genes were observed when comparing SPTCL with LEP cases; and overlapping with LEP cases. Gene set enrichment analysis recognized gene sets defining each group. In conclusion, SPTCL and LEP have distinctive molecular profiles and the molecular background of overlapping cases more closely resembles LEP.

Nodal peripheral T-cell lymphomas (n-PTCL) are aggressive lymphomas with no specific treatment. Programmed death 1 (PD-1) inhibits T-cell activation and proliferation, and the expression of its ligand PD-L1 has been associated with worse prognosis in some tumors. We performed immunohistochemistry for PD-1, p-STAT3, and PD-L1 (Clones SP142/263/22C3/28.8) and FISH studies for PD-L1/2 genes in chromosome 9p in a series of 168 formalin-fixed, paraffin-embedded n-PTCL samples. PD-L1 (clone 263) was the most frequently detected in both tumor cells (especially in the ALCL subgroup) and the microenvironment (especially in the AITL subgroup). In five ALCL cases, 3-4 copies of the two loci of chromosome 9 were found, suggestive of polyploidy. PD-L1 correlated with p-STAT3 on tumor cells. PD-1 expression in tumor cells was related to expression of PD-L1 in microenvironment. The expression of PD-L1 on tumor cells or microenvironment suggests that some n-PTCL cases might benefit from immune check-point modulation therapy.

Acral lymphomatoid papulosis (a-LyP) is a rare clinical variant of LyP whose diagnosis may be challenging. A case series of a-LyP was studied clinically, histopathologically, immunohistochemically and from molecular point of view. Including ours, 25 cases of a-LyP have so far been reported. Clinically, a-LyP may present with exclusive acral involvement, associate mucosal lesions, which is a rare presentation by itself; or may be associated to conventional LyP. The age of presentation was slightly higher than that of conventional LyP (55 vs 45 years) and a male predominance has been observed, as usually reported. Histopathologically, no morphological differences with conventional LyP were observed. LyP type A and E where the main variants. We describe for the first time one case of type D a-LyP. Acral LyP is a rare entity and correct diagnosis can only be reached with clinical and histopathological correlation, so as to avoid aggressive treatment of this indolent lymphoproliferative disorder. This article is protected by copyright. All rights reserved.

Introduction: Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is an unusual form of T-cell non-Hodgkin lymphoma. Surgical management is essential; however, adjuvant therapy is recommended for advanced stages of cancer. Case Presentation: A 40-year-old woman with textured silicone implants placed 7 years earlier, presented with breast nodules. Physical examination and computed tomography (CT) revealed a left parasternal mass, 2 left-breast nodules, and axillary lymphadenopathies. A soft-tissue lesion in the anterior mediastinum consistent with thymic remnants was detected. BIA-ALCL was diagnosed based on ultrasound-guided core biopsies of an axillary lymph node and a breast nodule. She underwent total bilateral capsulectomy and received anthracycline-based adjuvant chemotherapy. End-of-treatment positron emission tomography-computed tomography (PET-CT) scan at 4 months showed no evidence of disease, except for the persistence of the mediastinal lesion (Deauville score 4). Three months later, a new PET-CT scan showed enlargement of the lesion and increased radiotracer uptake, suggesting metabolic progression. A mediastinal biopsy was performed and rebound thymic hyperplasia (RTH) was observed in the histopathologic study. Once complete remission (CR) was achieved, the patient was followed up continually and has shown no signs of relapse to date. Conclusions: Further studies are required to determine the best adjuvant therapy for advanced BIA-ALCL. RTH may be suspected when thymic enlargement without the involvement of other areas is observed in patients with cancer. Mediastinal biopsy is mandatory to rule out relapse.

The spectrum of COVID-19 infection includes acute respiratory distress syndrome (ARDS) and macrophage activation syndrome (MAS), although the histological basis for these disorders has not been thoroughly explored. Post-mortem pulmonary and bone marrow biopsies were performed in 33 patients. Samples were studied with a combination of morphological and immunohistochemical techniques. Bone marrow studies were also performed in three living patients. Bone marrow post-mortem studies showed striking lesions of histiocytic hyperplasia with hemophagocytosis (HHH) in most (16/17) cases. This was also observed in three alive patients, where it mimicked the changes observed in hemophagocytic histiocytosis. Pulmonary changes included a combination of diffuse alveolar damage with fibrinous microthrombi predominantly involving small vessels, in particular the alveolar capillary. These findings were associated with the analytical and clinical symptoms, which helps us understand the respiratory insufficiency and reveal the histological substrate for the macrophage activation syndrome-like exhibited by these patients. Our results confirm that COVID-19 infection triggers a systemic immune-inflammatory disease and allow specific therapies to be proposed.

Primary cutaneous acral CD8-positive T-cell lymphoma consists of slow-growing nodules in acral sites with a histopathology, suggesting high-grade lymphoma despite the indolent clinical course. It has been recently included in WHO-EORTC classification for primary cutaneous lymphomas as a provisional entity. A correct diagnosis of this entity is important because its differential diagnosis include more aggressive cutaneous lymphomas. We present a 53-year-old woman with an indolent solitary nodule on her right leg, which histopathologically showed features of CD8-positive T-cell lymphoma, although with some peculiarities, including epidermotropism, absence of CD68 expression, and positivity for GATA3 and Bcl6 in neoplastic cells. This case could contribute to better define the spectrum of this rare cutaneous lymphoma.

Hematopoiesis is a hierarchical process by which pluripotent hematopoietic stem cells (HSCs) give rise to more differentiated and committed progenitors. Common progenitors subsequently differentiat...

Follicular helper T (TFH) cells are the providers of T-cell help to B-cells in the development of germinal centers and for the generation of most class-switched antibodies. The markers most commonly associated with TFH activity are IL21, IL4, CD40L, BCL6, SAP, CXCR5/CXCL13, and ICOS. T-cell lymphoma genomic studies have shown that different T-cell lymphoma types express signatures typical for TFH cells, this including angioimmunoblastic T-cell lymphoma (AITL), a related condition termed peripheral T-cell lymphoma with TFH phenotype and primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder. Angioimmunoblastic T-cell lymphoma is a well-established entity, a clinically aggressive disease with a survival of 30% OS after 5 years. Molecular and clinical studies have confirmed this as a well-established clinicopathological entity with relatively specific gene mutations, including mutations found in hematopoietic precursor cells and others. Peripheral T-cell lymphoma with TFH phenotype is an associated disorder with histology of PTCL but a TFH phenotype, as defined by the expression of 2-3 immunohistochemical markers. Molecular studies on this entity are showing a partial overlap with AITL. Primary cutaneous CD4+ small/medium lymphoproliferative disorder is an entirely different process that takes place in the skin, showing frank cytologic atypia, monoclonal TCR rearrangement and TFH phenotype in the context of a clinically benign lesion. Here we review the main clinical, molecular and diagnostic features of these three lymphoproliferative processes.

Pagetoid reticulosis (PR) is a rare lymphoproliferative disorder with indolent behavior considered a variant of mycosis fungoides. It is characterized by marked epidermotropism of the neoplastic lymphocytes. Since its original description, five cases have been reported in children. We report a new case of PR with an immunohistochemical profile not previously described in children.

Hepatosplenic T-cell lymphoma (HSTL) is an uncommon, aggressive peripheral T-cell lymphoma with a dismal prognosis, usually expressing gamma-delta T-cell receptor on immunohistochemical study. We report the second instance in the literature of a solitary skin nodule heralding recurrence of HSTL. The patient was a 40-year-old man in apparent remission from HSTL, 4 years after chemotherapy and autologous bone marrow transplant. Biopsy of a flank lesion showed atypical lymphoid cells involving the dermis with a perivascular and periadnexal pattern, and fat lobules of the subcutaneous tissue. Their phenotype mirrored that of previous biopsies, with expression of CD2, CD3, CD7, CD56, and T-cell receptor-gamma, and lack of T-cell receptor-beta, CD4, CD5, and CD8. Cutaneous involvement by HSTL has rarely been reported either at initial diagnosis or at recurrence, and represents a diagnostic pitfall for primary cutaneous gamma-delta T-cell lymphoma.

The presence of CD30 cells in cutaneous lymphomas has come to prominence in recent years as a potential diagnostic and therapeutic marker. In primary cutaneous marginal zone B-cell lymphomas, the presence of large CD30 cells with Hodgkin-like features and their significance have not yet been studied. Here we describe the main clinical, histologic, immunophenotypic, and molecular characteristics of 13 cases of primary cutaneous marginal zone lymphomas featuring >10% of CD30 large cells, and analyze their relationship with histologic and clinical progression of the disease and with other morphologic and immunophenotypic features. We report 10 male and 3 female patients, 4 with early-local disease and 8 with locoregional advanced disease without extracutaneous involvement but with a high relapse rate of 69%. We describe an association between a high level of CD30 expression and disease progression, with increased clinical recurrence in cases with >15% of CD30 cells. We also discuss the differential diagnosis with other cutaneous and systemic lymphomas, especially Hodgkin lymphoma.

Primary cutaneous CD30-positive T-cell lymphoproliferative disorders are the second most common subgroup of cutaneous T-cell lymphomas. They include two clinically different entities with some overlapping features and borderline cases: lymphomatoid papulosis and primary cutaneous anaplastic large cell lymphoma. Molecular studies of primary cutaneous anaplastic large cell lymphoma reveal an increasing level of heterogeneity that is associated with histological and immunophenotypic features of the cases and their response to specific therapies. Here, we review the most significant genetic, epigenetic and molecular alterations described to date in primary cutaneous CD30-positive T-cell lymphoproliferative disorders, and their potential as therapeutic targets., This work was supported by grants from the Instituto de Salud Carlos III (ISCIII) of the Spanish Ministry of Economy and Competence (MINECO, RTICC ISCIII and CIBERONC) (SAF2013-47416-R, RD06/0020/0107-RD012/0036/0060 and Plan Nacional I+D+I: PI17/2172, PI16/01294 and PIE15/0081), AECC and the Madrid Autonomous Community.

Nodal peripheral T-cell lymphomas (n-PTCL) are aggressive lymphomas with no specific treatment. Programmed death 1 (PD-1) inhibits T-cell activation and proliferation, and the expression of its ligand PD-L1 has been associated with worse prognosis in some tumors. We performed immunohistochemistry for PD-1, p-STAT3, and PD-L1 (Clones SP142/263/22C3/28.8) and FISH studies for

We investigated the clinicopathological features and prognostic factors of patients with peripheral T-cell lymphoma (PTCL) in 13 sites across Spain. Relevant clinical antecedents, CD30 expression and staining pattern, prognostic indices using the International Prognostic Index and the Intergruppo Italiano Linfomi system, treatments, and clinical outcomes were examined. A sizeable proportion of 175 patients had a history of immune-related disorders (autoimmune 16%, viral infections 17%, chemo/radiotherapy-treated carcinomas 19%). The median progression-free survival (PFS) and overall survival (OS) were 7·9 and 15·8 months, respectively. Prognostic indices influenced PFS and OS, with a higher number of adverse factors resulting in shorter survival (P 15% of cells were positive in anaplastic lymphoma kinase-positive and -negative anaplastic large-cell lymphoma and extranodal natural killer PTCL groups. We observed PTCL distribution across subtypes based on haematopathological re-evaluation. Poor prognosis, effect of specific prognostic indices, relevance of histopathological sub-classification, and response level to first-line treatment on outcomes were confirmed. Immune disorders amongst patients require further examination involving genetic studies and identification of associated immunosuppressive factors., This study was sponsored by Takeda.

Key Points Gene expression and mutational analysis confirm the differences among the 3 peripheral TCL subclasses: AITL, PTCL-NOS, and PTCL-TFH.The expression of a gene set, including B-cell genes, is an IPI-independent prognostic factor for AITL cases., Visual Abstract, Peripheral T-cell lymphoma (PTCL) is a clinically aggressive disease, with a poor response to therapy and a low overall survival rate of approximately 30% after 5 years. We have analyzed a series of 105 cases with a diagnosis of PTCL using a customized NanoString platform (NanoString Technologies, Seattle, WA) that includes 208 genes associated with T-cell differentiation, oncogenes and tumor suppressor genes, deregulated pathways, and stromal cell subpopulations. A comparative analysis of the various histological types of PTCL (angioimmunoblastic T-cell lymphoma [AITL]; PTCL with T follicular helper [TFH] phenotype; PTCL not otherwise specified [NOS]) showed that specific sets of genes were associated with each of the diagnoses. These included TFH markers, cytotoxic markers, and genes whose expression was a surrogate for specific cellular subpopulations, including follicular dendritic cells, mast cells, and genes belonging to precise survival (NF-κB) and other pathways. Furthermore, the mutational profile was analyzed using a custom panel that targeted 62 genes in 76 cases distributed in AITL, PTCL-TFH, and PTCL-NOS. The main differences among the 3 nodal PTCL classes involved the RHOAG17V mutations (P < .0001), which were approximately twice as frequent in AITL (34.09%) as in PTCL-TFH (16.66%) cases but were not detected in PTCL-NOS. A multivariate analysis identified gene sets that allowed the series of cases to be stratified into different risk groups. This study supports and validates the current division of PTCL into these 3 categories, identifies sets of markers that can be used for a more precise diagnosis, and recognizes the expression of B-cell genes as an IPI-independent prognostic factor for AITL.

The Epstein-Barr virus (EBV), Kaposi sarcoma herpesvirus (KSHV) and human T-lymphotropic virus (HTLV-1) are lymphomagenic viruses with region-specific induced morbidity. The RIAL-CYTED aims to increase the knowledge of lymphoma in Latin America (LA), and, as such, we systematically analyzed the literature to better understand our risk for virus-induced lymphoma. We observed that high endemicity regions for certain lymphomas, e.g., Mexico and Peru, have a high incidence of EBV-positive lymphomas of T/NK cell origin. Peru also carries the highest frequency of EBV-positive classical Hodgkin lymphoma (HL) and EBV-positive diffuse large B cell lymphoma, not otherwise specified (NOS), than any other LA country. Adult T cell lymphoma is endemic to the North of Brazil and Chile. While only few cases of KSHV-positive lymphomas were found, in spite of the close correlation of Kaposi sarcoma and the prevalence of pathogenic types of KSHV. Both EBV-associated HL and Burkitt lymphoma mainly affect young children, unlike in developed countries, in which adolescents and young adults are the most affected, correlating with an early EBV seroconversion for LA population despite of lack of infectious mononucleosis symptoms. High endemicity of KSHV and HTLV infection was observed among Amerindian populations, with differences between Amazonian and Andean populations. Fil: Chabay, Paola Andrea. Gobierno de la Ciudad de Buenos Aires. Instituto Multidisciplinario de Investigaciones en Patologías Pediátricas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto Multidisciplinario de Investigaciones en Patologías Pediátricas; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentina Fil: Lens, Daniela. Universidad de la Republica. Facultad de Medicina. Hospital de Clínicas "dr. Manuel Quintela".; Uruguay Fil: Hassan, Rocio. National Cancer Institute “José Alencar Gomes da Silva”; Brasil Fil: Rodríguez Pinilla, Socorro María. University Hospital, Fundación Jiménez Díaz; España Fil: Valvert Gamboa, Fabiola. Cancer Institute and National League against Cancer; Guatemala Fil: Rivera, Iris. Salvadoran Institute of Social Security; El Salvador Fil: Huamán Garaicoa, Fuad. Santiago de Guayaquil Catholic University; Ecuador Fil: Ranuncolo, Stella Maris. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Barrionuevo, Carlos. National University of San Marcos; Perú Fil: Morales Sánchez, Abigail. Children’s Hospital of Mexico Federico Gómez; México Fil: Scholl, Vanesa. No especifíca; Fil: de Matteo, Elena Noemí. Gobierno de la Ciudad de Buenos Aires. Instituto Multidisciplinario de Investigaciones en Patologías Pediátricas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto Multidisciplinario de Investigaciones en Patologías Pediátricas; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentina Fil: Preciado, María Victoria. Gobierno de la Ciudad de Buenos Aires. Instituto Multidisciplinario de Investigaciones en Patologías Pediátricas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto Multidisciplinario de Investigaciones en Patologías Pediátricas; Argentina. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentina Fil: Fuentes Pananá, Ezequiel M.. Children’s Hospital of Mexico Federico Gómez; México

Background Next-generation sequencing (NGS) is a high-throughput technology that has become widely integrated in molecular diagnostics laboratories. Among the large diversity of NGS-based panels, the Trusight Tumor 26 (TsT26) enables the detection of low-frequency variants across 26 genes using the MiSeq platform. Methods We describe the inter-laboratory validation and subsequent clinical application of the panel in 399 patients presenting a range of tumor types, including gastrointestinal (GI, 29%), hematologic (18%), lung (13%), gynecological and breast (8% each), among others. Results The panel is highly accurate with a test sensitivity of 92%, and demonstrated high specificity and positive predictive values (95% and 96%, respectively). Sequencing testing was successful in two-thirds of patients, while the remaining third failed due to unsuccessful quality-control filtering. Most detected variants were observed in the TP53 (28%), KRAS (16%), APC (10%) and PIK3CA (8%) genes. Overall, 372 variants were identified, primarily distributed as missense (81%), stop gain (9%) and frameshift (7%) altered sequences and mostly reported as pathogenic (78%) and variants of uncertain significance (19%). Only 14% of patients received targeted treatment based on the variant determined by the panel. The variants most frequently observed in GI and lung tumors were: KRAS c.35G > A (p.G12D), c.35G > T (p.G12V) and c.34G > T (p.G12C). Conclusions Prior panel validation allowed its use in the laboratory daily practice by providing several relevant and potentially targetable variants across multiple tumors. However, this study is limited by high sample inadequacy rate, raising doubts as to continuity in the clinical setting.

The overlap of morphology and immunophenotype between angioimmunoblastic T-cell lymphoma (AITL) and other nodal peripheral T-cell lymphomas (n-PTCLs) is a matter of current interest whose clinical relevance and pathogenic background have not been fully established. We studied a series of 98 n-PTCL samples (comprising 57 AITL and 41 PTCL-NOS) with five TFH antibodies (CD10, BCL-6, PD-1, CXCL13, ICOS), looked for mutations in five of the genes most frequently mutated in AITL (TET2, DNMT3A, IDH2, RHOA and PLCG1) using the Next-Generation-Sequencing Ion Torrent platform, and measured the correlations of these characteristics with morphology and clinical features. The percentage of mutations in the RHOA and TET2 genes was similar (23.5% of cases). PLCG1 was mutated in 14.3%, IDH2 in 11.2% and DNMT3A in 7.1% of cases, respectively. In the complete series, mutations in RHOA gene were associated with the presence of mutations in IDH2, TET2 and DNMT3A (p < 0.001, p = 0.043, and p = 0.029, respectively). Fourteen cases featured RHOA mutations without TET2 mutations. A close relationship was found between the presence of these mutations and a TFH-phenotype in AITL and PTCL-NOS patients. Interestingly, BCL-6 expression was the only TFH marker differentially expressed between AITL and PTCL-NOS cases. There were many fewer mutated cases than there were cases with a TFH phenotype. Overall, these data suggest alternative ways by which neoplastic T-cells overexpress these proteins. On the other hand, no clinical or survival differences were found between any of the recognized subgroups of patients with respect to their immunohistochemistry or mutational profile. This work was supported by grants from the Instituto de Salud Carlos III, from the Ministerio de Economía, Industria y Competitividad (RTICC RD06/0020/0107, RD12/0036/0060, PI 12/1682, PT13/0010/0007, PI16/ 01294, SAF2013-47416-R, CIBERONC-ISCIII, PIE15/ 0081, ISCIII-MINECO AES-FEDER (Plan Estatal I+D+I 2013–2016): PI14/00221, PIE14/0064, PIE15/0081 and PIE16/01294)) and the Asociación Española Contra el Cáncer, Spain. JG-R is a recipient of an iPFIS predoctoral fellowship (IFI14/00003) from ISCIII-MINECO-AESFEDER (Plan Estatal I+D+I 2013–2016). MSB was supported by a Miguel Servet contract (CP11/00018) from the ISCIII-MINECO-AES-FEDER (Plan Nacional I+D+I 2008–2011), and currently holds a Miguel Servet II contract (CPII16/00024), supported by ISCIII-MINECOAES- FEDER (Plan Estatal I+D+I 2013–2016) and the Fundación de Investigación Biomédica Puerta de Hierro. Sí

Introduction: Nodal peripheral T-cell lymphoma (PTCL) subclassification (Angioimmunoblastic TCL, PTCL-with T Follicular Helper phenotype and PTCL-NOS) and therapeutic targeting is still controversial. Overall survival (OS) is only around 30% after 5 years. Methods: We performed targeted next-generation sequencing of 61 selected genes in 76 PTCL patients. Among the 76cases, 44 were classified as AITL, 18 as PTCL-TFH and 14 as PTCL-NOS. Results: Our analysis revealed a wide variety of genetic variants that possibly drive the development of AITL, PTCL-TFH and/or PTCL-NOS. We identified an average of 4 variants per patient, mainly clustered in genes regulating chromatin conformation (TET2, DNMT3A) and T-cell differentiation (RHOA, MTOR, IDH2, VAV1 and NOTCH1). More frequently mutated genes were TET2 (76,31%) and DNMT3A (27,63%). Multiple mutations were found in TET2, VAV1, RHOA, NOTCH1, MTOR, JAK1, ZEB1, ATM, DNMT3A and ARID1B. Main difference among the three Nodal PTCL classes was the higher frequency of RHOAG17V mutations (p Conclusions: There is a common molecular basis for the three Nodal PTCL with very frequent mutations in genes regulating chromatin conformation associated with mutations in genes governing T-cell differentiation. RHOA G17V mutations were highly significant enriched in AITL. Findings suggesting Clonal Hematopoiesis were found in the three types of nodal PTCL.

Cutaneous manifestations of Waldenstrom macroglobulinemia may occur due to several mechanisms, the least common being direct skin infiltration by neoplastic cells. We report a case of patient that after 4-year history of indolent Waldenstrom macroglobulinemia developed skin infiltration by lymphoplasmacytoid cells in the form of a small, mildly indurated plaque on the anterior chest. MYD88 L265P mutation was detected both in the previous bone marrow biopsy and in the cutaneous lesion. We review the impact of this new genetic tool in the diagnosis and treatment of lymphoplasmacytic proliferations.

Aims To present four examples of clonally related Epstein-Barr virus (EBV)-associated large-cell transformation of marginal zone lymphoma (MZL) (of nodal, extranodal and splenic types), occurring 120, 11 and 5 months after the initial diagnosis in three instances, and concurrently in one case; and to discuss several interesting features of EBV infection. Methods and results Somatic mutations were detected by use of a customised panel for next-generation sequencing and polymerase chain reaction studies of IgH in both low-grade and high-grade components of each case. In case 1, the initial biopsy of nodal MZL showed scattered EBV-positive cells, which might constitute an indication of EBV-induced progression. Case 2 showed heterogeneous EBV expression, a phenomenon attributable to loss of the EBV episomes during cell division, or to a secondary superinfection or reactivation of the virus. In case 3, p53 overexpression related to gene mutation and EBV-encoded small RNAs were identified in the same neoplastic component. In case 4, the mucosa-associated lymphoid tissue-type MZL and the high-grade component were identified concurrently in a patient previously treated with methotrexate for an autoimmune disorder. Conclusion These data suggest that the presence of EBV should be added to the list of potential markers to be analysed for MZL prognosis.

We report on a 74-year-old man with a cutaneous B-cell follicle center lymphoma, which was treated upfront with systemic rituximab and suffered several local relapses. The first of the local recurrences, 10 months after completion of treatment, was characterized by a dense T-cell infiltrate that obscured a minor population of B-cell lymphoma cells, suggesting a second primary cutaneous T-cell lymphoma. This represents a previously not reported diagnostic pitfall and underscores the importance of performing sequential biopsies when dealing with lymphoma recurrences in this setting.

Cutaneous eruption of lymphocyte recovery (ELR) during bone marrow (BM) aplasia recovery after intensive chemotherapy has been reported in very few patients. The presence of skin rashes in patients with acute leukemia who are undergoing intensive chemotherapy and BM transplantation is a diagnostic challenge because of the clinical similarity between drug eruptions, infiltrates related to the relapse of the underlying disease, cutaneous graft-versus-host disease, and ELR. IDH1 mutations have been identified as a recurrent genetic anomaly in acute myeloid leukemia and myelodysplastic syndromes. However, until now, this IDH1 mutation has not been reported as being shared by myeloid cells and non-neoplastic inflammatory cells in this clinical setting. Here, we present the rare case of a woman diagnosed with myelodysplastic syndrome that evolved into an acute myelogenous leukemia with leukemic cutaneous infiltrate. The patient developed ELR after the intensive chemotherapy administered before BM transplantation. The IDH1 mutation was identified in BM cells and in myeloid and inflammatory cells in skin biopsies before allogeneic BM transplantation. We discuss the main aspects of the differential diagnosis of these cutaneous reactions in leukemic patients and the biological significance of the IDH1 mutation.

BACKGROUND: The malignant mechanisms that control the development of cutaneous T-cell lymphoma (CTCL) are beginning to be identified. Recent evidence suggests that disturbances in specific intracellular signalling pathways, such as RAS-mitogen-activated protein kinase, T-cell receptor (TCR)-phospholipase C gamma 1 (PLCG1)-nuclear factor of activated T cells (NFAT) and Janus kinase (JAK)-signal transducer and activator of transcription (STAT), may play an essential role in the pathogenesis of CTCL. OBJECTIVES: To investigate the mechanisms controlling disease development and progression in mycosis fungoides (MF), the most common form of CTCL. METHODS: We collected 100 samples that were submitted for diagnosis of, or a second opinion regarding, MF between 2001 and 2018, 80% of which were in the early clinical stages of the disease. Formalin-fixed paraffin-embedded tissues were used for histological review and to measure the expression by immunohistochemistry of surrogate markers of activation of the TCR-PLCG1-NFAT, JAK-STAT and NF-?B pathways. Folliculotropism and large-cell transformation were also examined. RESULTS: NFAT and nuclear factor kappa B (NF-?B) markers showed a comparable activation status in early and advanced stages, while STAT3 activation was more frequent in advanced stages and was associated with large-cell transformation. Consistently with this observation, STAT3 activation occurred in parallel with MF progression in two initially MF-negative cases. A significant association of NFAT with NF-?B markers was also found, reflecting a common mechanism of activation in the two pathways. Genomic studies identified nine mutations in seven genes known to play a potential role in tumorigenesis in T-cell leukaemia/lymphoma, including PLCG1, JAK3 and STAT3, which underlies the activation of these key cell-survival pathways. A higher mutational allele frequency was detected in advanced stages. CONCLUSIONS: Our results show that STAT3 is activated in advanced cases and is associated with large-cell transformation, while the activation of NFAT and NF-?B is maintained throughout the disease. These findings could have important diagnostic and therapeutic implications. What's already known about this topic? Mycosis fungoides is characterized by a clonal expansion of T cells in the skin. The mechanisms controlling disease development and progression are not fully understood. What does this study add? An association of the nuclear factor of activated T cells and nuclear factor kappa B pathways was found, which could reflect a common mechanism of activation. These pathways were activated in early and advanced stages at the same level. Signal transducer and activator of transcription 3 activation was associated with large-cell transformation and was more frequent in advanced stages. A genomic analysis of cutaneous T-cell lymphoma-associated genes was performed. Nine mutations were detected. What is the translational message? These results could have important implications for the treatment of MF in the near future. Funding: This study has been supported by grants from the Instituto de Salud Carlos III, from the Ministerio de Economía, Industria y Competitividad (SAF2013-47416-R, CIBERONC-ISCIII, ISCIII-MINECO-AES-FEDER (Plan Estatal I + D + I 2013–2016): PI14/00221, PIE14/0064, PIE15/0081, PIE16/01294, and FIS 17/0957)), Asociación española contra el Cáncer (AECC), Comunidad Autónoma de Madrid and from the Instituto Formación e Investigación Hospital Universitario Marqués de Valdecilla (IDIVAL): NVAL16/18.

Mycosis fungoides (MF) is the most common type of cutaneous T-cell lymphoma, primary cutaneous CD30 lymphoproliferative disorders (pc CD30 LPD) being the second most prevalent. There is evidence that MF and pc CD30 LPD may coexist and share T-cell clonality, suggesting a common origin. These findings were supported by a T-cell receptor clonality assessment by the polymerase chain reaction coupled with capillary electrophoresis, although results produced by this method may be ambiguous. We describe an otherwise healthy 46-year-old man who developed, over the course of 5 months, a tumor consisting of primary cutaneous anaplastic large cell lymphoma and, subsequently, several papules of lymphomatoid papulosis (LyP). Both lymphomas appeared on a single patch of MF, which had been present on the patient's right buttock for at least 2 years. T-cell receptor clonality of the 3 types of neoplastic lesions and apparently non-involved skin were assessed by a next-generation sequencing-based method. We found that MF, primary cutaneous anaplastic large cell lymphoma and LyP harbored the same top 2 clones. Non-involved skin harbored other T-cell clones. In this patient, these findings suggest that MF, LyP and pc CD30 LPD were different clinicopathological manifestations arising from the neoplastic proliferation of the same T-cell clone.

Follicular lymphoma (FL) is an indolent but largely incurable disease. Some patients suffer histological transformation to a more aggressive subtype with poorer prognosis. This study aimed to improve our understanding of the genetics underlying FL histological transformation, and to identify genetic drivers or promoters of the transformation by elucidating the differences between FL samples from patients who did and did not transform. We conducted targeted massive parallel sequencing of 22 pre-transformed FL/transformed diffuse large B-cell lymphoma pairs and 20 diagnostic samples from non-transformed FL patients. Additionally, 22 matched samples from 11 transformed FL patients (pre-transformed FL and diffuse large B-cell lymphoma) and 9 non-transformed FLs were studied for copy number variation using SNP arrays. We identified recurrently mutated genes that were enriched at transformation, most notably LRP1B, GNA13 and POU2AF1, which have roles in B-cell differentiation, GC architecture and migration. Mutations in POU2AF1 might be associated with lower levels of expression, were more frequent in transformed FLs, and seemed to be specific to transformed- compared with de novo-diffuse large B-cell lymphomas. Pre-transformed FLs carried more mutations per sample and had greater subclonal heterogeneity than non-transformed FLs. Finally, we identified four mutated genes in FL samples that differed between patients who did and did not transform: NOTCH2, DTX1, UBE2A and HIST1H1E. The presence of mutations in these genes was associated with shorter time to transformation when mutated in the FL biopsies. This information might be useful for identifying patients at higher risk of transformation.