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Anaplastic large cell lymphoma (ALCL) shows a wide morphologic spectrum, including the occurrence of reactive components obscuring the neoplastic population. This makes its distinction from hyperimmune reaction difficult. The authors describe an ALCL in a girl wha had a tick bite 20 days prior to clinical presentation. She developed a huge epithelioid reaction (an unprecedented finding for this tumor). The diagnostic controversies were solved by applying the ALKc antibody against anaplastic large cell lymphoma kinase (ALK), in conjunction with reagents anti-nucleophosmin (NPM), which showed the typical staining pattern observed in ALCL carrying t(2;5). Comprised within the epithelioid component there were large anaplastic cells and small-medium sized atypical elements displaying strong nuclear and cytoplasmic positivity for ALK and NPM (N-terminal region). This pattern, never observed in normal lymphocytes, corresponds to the presence of the product of the hybrid gene NPM/ALK produced by t(2;5). Following the diagnosis, the patient - whose general conditions were critical - underwent aggressive chemotherapy, achieving complete remission.

Castleman's disease, also known as benign giant lymph node hyperplasia, is a lymphoproliferative disorder which can occur either in a localized or multicentric form. The latter is characterized by the development of malignant lymphoma, Kaposi's sarcoma or carcinoma in 32% of cases. By contrast, localized Castleman's disease has exceptionally been reported in association with non-Hodgkin's lymphoma and - to the best of our knowledge - never at the same anatomic site. Here we describe the occurrence in the same lymph node of localized Castleman's disease (with monotypic plasma cell component) and an apparently unrelated peripheral small B-lymphocytic lymphoma.

With the development and refinement of new guidance methods for percutaneous biopsies, many investigators have reported studies supporting a role for radiologically guided core-needle biopsy in the diagnosis of malignant lymphoma under certain clinical circumstances. The aims of this report are to evaluate the efficacy of findings at ultrasound (US)-guided core-needle biopsy of abdominal lymphoma on patient care and define the key determinants of clinical success.US-guided core needle biopsies were performed in 55 patients with abdominal lymphoma: 44 non-Hodgkin's lymphoma (NHL) and 11 Hodgkin's disease (HD); 41 had had no prior lymphoma and 14 had previously diagnosed lymphoma. All the biopsies were performed under US control using a 21-gauge modified Menghini needle. Overall, 53/55 (96%) patients were treated on the basis of biopsy findings only, including 14/14 (100%) patients with a history of lymphoma and 39/41 (93%) patients with no such history.In 46/53 (87%) patients it was possible to assess the specific histotype. No differences between the diagnostic rates of HD and high grade-NHL were recorded. There were no complications related to the biopsies.Our data indicate that abdominal US-guided core-needle biopsy should be considered as an effective and safe procedure in the diagnosis of patients with lymphoma offering the possibility of determining the tumor subtype and the subsequent specific treatment.

T-cell-rich B-cell lymphoma is a rare variant of diffuse large B-cell lymphoma. It shows morphologic, phenotypic and molecular similarities to lymphocyte predominant Hodgkin's disease, and in consequence the two diseases may sometimes be difficult to distinguish. In this paper, we have evaluated the usefulness of the pan-leukocyte marker LSP1 and the transcription factor PU.1 for resolving such diagnostic problems.Immunohistochemical techniques were used to investigate the expression of LSP1 and PU.1 in 34 tumors, comprising typical examples of T-cell-rich B-cell lymphoma (15 cases), lymphocyte-predominant Hodgkin's disease (13 cases), and lymphocyte-rich classical Hodgkin's disease (6 cases).The neoplastic cells of T-cell-rich B-cell lymphoma were LSP1-positive and PU.1-negative, whereas the lymphocytic and/or histiocytic (LH) cells of lymphocyte-predominant Hodgkin's disease were mostly LSP1-negative, with variable PU.1 expression. The two markers did not discriminate between T-cell-rich B-cell lymphoma and lymphocyte-rich classical Hodgkin's disease, whilst they concurred to the distinction between lymphocyte-predominant and lymphocyte-rich classical Hodgkin's disease by integrating the already available tools.Antibodies to LSP1 and PU.1 may represent useful reagents for the differential diagnosis between T-cell-rich B-cell lymphoma and lymphocyte-predominant Hodgkin's disease.

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A retrospective analysis was performed to assess the efficacy of various treatments of non-Hodgkin's primary bone lymphomas (PBL).Fifty-two consecutive, previously untreated PBL patients were seen between the years 1982 and 1998. Information was obtained regarding each patient's presentation and clinical course. Histology was reviewed in all cases. Modern immunohistochemical stains were performed on each case.Regarding therapeutic approach, we observed a complete response (CR) in 35/41 (85%) patients treated with chemotherapy with/without radiation therapy and in 7/11 (64%) patients who received radiation therapy alone. Relapses were observed in only 2/35 (6%) patients after chemotherapy (with/without radiation therapy), as compared with 4/7 (57%) patients after radiation therapy alone (p = 0.004); the relapse-free survival curves of these two subsets were significantly different. At both univariate and multivariate analysis only type of front-line therapeutic approach (chemotherapy with/without radiation therapy vs. radiation therapy alone) turned out to have a significant prognostic influence.Our data indicate that in PBL use of chemotherapy or combined-modality therapy seems to provide more durable CRs than radiation therapy alone.

The RING-finger promyelocytic leukemia (PML) protein is the product of the PML gene that fuses with the retinoic acid receptor-alpha gene in the t(15; 17) translocation of acute promyelocytic leukemia. Wild-type PML localizes in the nucleus with a typical speckled pattern that is a consequence of the concentration of the protein within discrete subnuclear domains known as nuclear bodies. Delocalization of PML from nuclear bodies has been documented in acute promyelocytic leukemia cells and suggested to contribute to leukemogenesis. In an attempt to get new insights into the function of the wild-type PML protein and to investigate whether it displays an altered expression pattern in neoplasms other than acute promyelocytic leukemia, we stained a large number of normal and neoplastic human tissues with a new murine monoclonal antibody (PG-M3) directed against the amino-terminal region of PML. As the PG-M3 epitope is partially resistant to fixatives, only cells that overexpress PML are detected by the antibody in microwave-heated paraffin sections. Among normal tissues, PML was characteristically up-regulated in activated epithelioid histiocytes and fibroblasts in a variety of pathological conditions, columnar epithelium in small active thyroid follicles, well differentiated foamy cells in the center of sebaceous glands, and hypersecretory endometria (Arias-Stella). Interferons, the PML of which is a primary target gene, and estrogens are likely to represent some of the cytokines and/or hormones that may be involved in the up-regulation of PML under these circumstances. In keeping with this concept, we found that PML is frequently overexpressed in Hodgkin and Reed-Sternberg cells of Hodgkin's disease, a tumor of cytokine-producing cells. Among solid tumors, overexpression of PML was frequently found in carcinomas of larynx and thyroid (papillary), epithelial thymomas, and Kaposi's sarcoma, whereas carcinomas of the lung, thyroid (follicular), breast, and colon were frequently negative or weakly PML+. We did not observe any changes in the levels of PML expression as the lesion progressed from benign dysplasia to carcinoma. Our immunohistological data are consistent with the hypothesized growth suppressor function of PML and strongly suggest that PML expression levels are likely to be modulated by a variety of stimuli, including cytokines and hormones.

Although primary mediastinal (thymic) large B-cell lymphoma has been primarily studied, its precise phenotype, molecular characteristics, and histogenesis are still a matter of debate. The International Extranodal Lymphoma Study Group collected 137 such cases for extensive pathological review. Histologically, the lymphomatous growth was predominantly diffuse with fibrosis that induced compartmentalized cell aggregation. It consisted of large cells with varying degrees of nuclear polymorphism and clear to basophilic cytoplasm. On immunohistochemistry, the following phenotype was observed: CD45(+), CD20(+), CD79a(+), PAX5/BSAP(+), BOB.1(+), Oct-2(+), PU.1(+), Bcl-2(+), CD30(+), HLA-DR(+), MAL protein(+/-), Bcl-6(+/-), MUM1/IRF4(+/-), CD10(-/+), CD21(-), CD15(-), CD138(-), CD68(-), and CD3(-). Immunoglobulins were negative both at immunohistochemistry and in situ hybridization. Molecular analysis, performed in 45 cases, showed novel findings. More than half of the cases displayed BCL-6 gene mutations, which usually occurred along with functioning somatic IgV(H) gene mutations and Bcl-6 and/or MUM1/IRF4 expression. The present study supports the concept that a sizable fraction of cases of this lymphoma are from activated germinal center or postgerminal center cells. However, it differs from other aggressive B-cell lymphomas in that it shows defective immunoglobulin production despite the expression of OCT-2, BOB.1, and PU.1 transcription factors and the lack of IgV(H) gene crippling mutations.

The REAL/WHO classification constitutes a new tool for the better understanding and treatment of malignant lymphomas. The authors focus on the key features of aggressive B- and T-cell lymphomas, aiming to contribute to the cross-talk between pathologists and clinicians.Each lymphoma entity is analyzed on the basis of the most representative contributions in the literature and the authors' experience gained in studying more than 20,000 lymphoid tumors over a 20-year period.Guidelines for diagnosis and areas of interest for future clinico-pathologic studies are identified and discussed. Within this context, selected data obtained by the application of novel markers are presented.The present know- ledge and organization of malignant lymphomas now make the development of tailored therapies a feasible goal.

Hairy-cell leukemia (HCL) is a CD20+ indolent B-cell cancer in which a BRAF V600E kinase-activating mutation plays a pathogenetic role. In clinical trials involving patients with refractory or relapsed HCL, the targeting of BRAF V600E with the oral BRAF inhibitor vemurafenib led to a response in 91% of the patients; 35% of the patients had a complete response. However, the median relapse-free survival was only 9 months after treatment was stopped.In a phase 2, single-center, academic trial involving patients with refractory or relapsed HCL, we assessed the safety and efficacy of vemurafenib (960 mg, administered twice daily for 8 weeks) plus concurrent and sequential rituximab (375 mg per square meter of body-surface area, administered for 8 doses over a period of 18 weeks). The primary end point was a complete response at the end of planned treatment.Among the 30 enrolled patients with HCL, the median number of previous therapies was 3. A complete response was observed in 26 patients (87%) in the intention-to-treat population. All the patients who had HCL that had been refractory to chemotherapy (10 patients) or rituximab (5) and all those who had previously been treated with BRAF inhibitors (7) had a complete response. Thrombocytopenia resolved after a median of 2 weeks, and neutropenia after a median of 4 weeks. Of the 26 patients with a complete response, 17 (65%) were cleared of minimal residual disease (MRD). Progression-free survival among all 30 patients was 78% at a median follow-up of 37 months; relapse-free survival among the 26 patients with a response was 85% at a median follow-up of 34 months. In post hoc analyses, MRD negativity and no previous BRAF inhibitor treatment correlated with longer relapse-free survival. Toxic effects, mostly of grade 1 or 2, were those that had previously been noted for these agents.In this small study, a short, chemotherapy-free, nonmyelotoxic regimen of vemurafenib plus rituximab was associated with a durable complete response in most patients with refractory or relapsed HCL. (Funded by the European Research Council and others; HCL-PG03 EudraCT number, 2014-003046-27.).

An accurate diagnosis of clinically distinct subgroups of aggressive mature B cell lymphomas is crucial for the choice of proper treatment. Presently, precise recognition of these disorders relies on the combination of morphological, immunophenotypical, and cytogenetic/molecular features. The diagnostic workup in such situations implies the application of costly and time-consuming analyses, which are not always required, since an intensified treatment option is reasonably reserved to fit patients. The Italian Group of Haematopathology proposes herein a practical algorithm for the diagnosis of aggressive mature B cell lymphomas based on a stepwise approach, aimed to select cases deserving molecular analysis, in order to optimize time and resources still assuring the optimal management for any patient.

Background: CD4+/CD56+ hematodermic neoplasm (HN) (blastic natural killer (NK)-cell lymphoma) is a rare entity characterized by dense, monomorphous infiltrates of medium-sized cells with blastic appearance and a characteristic immunophenotype (positivity for CD4, CD56 and CD123). The combination of CD4 and CD56 positivity is thought to be so striking that it has been used to name this entity. Methods: Three cases of HN with ambiguous phenotypic profile were included in this study. In all cases, phenotypic, molecular and in situ hybridization studies were carried out. Results: All three cases showed an aberrant phenotype with negativity for CD4. Conclusions: CD4-negative or CD56-negative cases of HN have been rarely reported in the literature and represent a diagnostic problem. Our three cases confirm that CD4 is not always expressed in these neoplasms. The term 'CD4+/CD56+ hematodermic neoplasm' adopted in the World Health Organization-European Organization for Research and Treatment of Cancer classification of cutaneous lymphomas may be misleading and should probably be revised in the light of all data published in the literature. © Blackwell Munksgaard 2008.

Myeloid sarcoma ( MS) is a rare neoplasm whose knowledge is largely based on case reports and/or technically dated contributions. Ninety-two MSs in adulthood with clinical data available were evaluated both morphologically and immunohistochemically. Seventy-four cases were also studied by fluorescent in situ hybridization on tissue sections and/or conventional karyotyping on bone marrow or peripheral blood. Histologically, 50% of the tumors were of the blastic type, 43.5% either monoblastic or myelomonocytic and 6.5% corresponded to different histotypes. CD68/KP1 was the most commonly expressed marker (100%), followed by myeloperoxidase (83.6%), CD117 (80.4%), CD99 (54.3%), CD68/PG-M1 (51%), CD34 (43.4%), terminal-deoxy-nucleotidyl-transferase (31.5%), CD56 (13%), CD61/linker for activation of T cells (2.2%), CD30 ( 2.2%) and CD4 (1.1%). Foci of plasmacytoid monocyte differentiation were observed in intestinal cases carrying inv16. Chromosomal aberrations were detected in about 54% of cases: monosomy 7(10.8%), trisomy 8(10.4%) and mixed lineage leukemia-splitting (8.5%) were the commonest abnormalities, whereas t(8; 21) was rare ( 2.2%). The behavior was dramatic irrespective of presentation, age, sex, phenotype and cytogenetics. Most if not all, long survivors received bone-marrow transplantation. The present report expands the spectrum of our knowledge showing that MS has frequent monoblastic/myelomonocytic differentiation, displays distinctive phenotypic profile, carries chromosomal aberrations other than t( 8; 21), and requires supra-maximal therapy.

Pembrolizumab (anti-PD-1) is allowed in selected metastatic castration-resistant prostate cancer (PC) patients showing microsatellite instability/mismatch repair system deficiency (MSI-H/dMMR). BRCA1/2 loss-of-function is linked to hereditary PCs and homologous recombination DNA-repair system deficiency: poly-ADP-ribose-polymerase inhibitors can be administered to BRCA-mutated PC patients. Recently, docetaxel-refractory metastatic castration-resistant PC patients with BRCA1/2 or ATM somatic mutations had higher response rates to pembrolizumab. PTEN regulates cell cycle/proliferation/apoptosis through pathways including the AKT/mTOR, which upregulates PD-L1 expression in PC. Our systematic literature review (PRISMA guidelines) investigated the potential correlations between PD-L1 and MMR/MSI/BRCA/PTEN statuses in PC, discussing few other relevant genes. Excluding selection biases, 74/677 (11%) PCs showed dMMR/MSI; 8/67 (12%) of dMMR/MSI cases were PD-L1+. dMMR-PCs included ductal (3%) and acinar (14%) PCs (all cases tested for MSI were acinar-PCs). In total, 15/39 (39%) PCs harbored BRCA1/2 aberrations: limited data are available for PD-L1 expression in these patients. 13/137 (10%) PTEN- PCs were PD-L1+; 10/29 (35%) PD-L1+ PCs showed PTEN negativity. SPOP mutations may increase PD-L1 levels, while the potential correlation between PD-L1 and ERG expression in PC should be clarified. Further research should verify how the efficacy of PD-1 inhibitors in metastatic castration-resistant PCs is related to dMMR/MSI, DNA-damage repair genes defects, or PD-L1 expression.

The tumor microenvironment (TME) includes immune (T, B, NK, dendritic), stromal, mesenchymal, endothelial, adipocytic cells, extracellular matrix, and cytokines/chemokines/soluble factors regulating various intracellular signaling pathways (ISP) in tumor cells. TME influences the survival/progression of prostate cancer (PC), enabling tumor cell immune-evasion also through the activation of the PD-1/PD-L1 axis. We have performed a systematic literature review according to the PRISMA guidelines, to investigate how the PD-1/PD-L1 pathway is influenced by TME and ISPs. Tumor immune-escape mechanisms include suppression/exhaustion of tumor infiltrating cytotoxic T lymphocytes, inhibition of tumor suppressive NK cells, increase in immune-suppressive immune cells (regulatory T, M2 macrophagic, myeloid-derived suppressor, dendritic, stromal, and adipocytic cells). IFN-γ (the most investigated factor), TGF-β, TNF-α, IL-6, IL-17, IL-15, IL-27, complement factor C5a, and other soluble molecules secreted by TME components (and sometimes increased in patients’ serum), as well as and hypoxia, influenced the regulation of PD-L1. Experimental studies using human and mouse PC cell lines (derived from either androgen-sensitive or androgen-resistant tumors) revealed that the intracellular ERK/MEK, Akt-mTOR, NF-kB, WNT and JAK/STAT pathways were involved in PD-L1 upregulation in PC. Blocking the PD-1/PD-L1 signaling by using immunotherapy drugs can prevent tumor immune-escape, increasing the anti-tumor activity of immune cells.

Immunotherapy targeting the PD-1–PD-L1 axis yielded good results in treating different immunologically ‘‘hot’’ tumors. A phase II study revealed good therapeutic activity of pembrolizumab in selected prostatic carcinoma (PC)-patients. We performed a systematic literature review (PRISMA guidelines), which analyzes the immunohistochemical expression of PD-L1 in human PC samples and highlights the pre-analytical and interpretation variables. Interestingly, 29% acinar PCs, 7% ductal PCs, and 46% neuroendocrine carcinomas/tumors were PD-L1+ on immunohistochemistry. Different scoring methods or cut-off criteria were applied on variable specimen-types, evaluating tumors showing different clinic-pathologic features. The positivity rate of different PD-L1 antibody clones in tumor cells ranged from 3% (SP142) to 50% (ABM4E54), excluding the single case tested for RM-320. The most tested clone was E1L3N, followed by 22C3 (most used for pembrolizumab eligibility), SP263, SP142, and 28-8, which gave the positivity rates of 35%, 11–41% (depending on different scoring systems), 6%, 3%, and 15%, respectively. Other clones were tested in