[Impact of SARS-CoV-2/COVID-19 on the placenta]. / SARS-CoV-2/COVID-19-Auswirkungen auf die Plazenta.

From the very beginning, special attention regarding severe acute respiratory syndrome-coronavirus­2 (SARS-CoV-2) and the resulting coronavirus disease-2019 (COVID-19) has been paid to pregnant women.In this review, after a short introduction into the immunodefensive role of the placenta and viral infections in general, we describe the morphological changes of the placenta in SARS-CoV-2-infected pregnant women based on our own and other published studies, draw comparisons to the SARS epidemic, and discuss the question of vertical transmission of SARS-CoV­2 from the mother to the neonate.The most common pathological findings of the placenta in SARS-CoV­2 infection are signs of maternal and fetal malperfusion as well as potentially immunologically and/or thromboinflammation-mediated findings. These manifest as infarcts and decidual vasculopathy as well as thrombi in the fetal circulation and avascular villi. In some cases, there is also an inflammatory reaction with villitis, intervillositis, and fetal vasculitis. In addition, it has been shown that SARS-CoV­2 can directly infect the placenta, so vertical transmission is possible.There is no COVID-19 specific pattern of placental alterations, although the detection of fetal thrombovasculitis, villitis, and intervillositis as well as fetal and maternal malperfusion could be best interpreted as the signature of SARS-CoV­2 infection - considering the known pathophysiology of COVID-19 regarding other organs (inflammatory reaction and [micro]angiopathy). Detection of viral RNA in the fetal placental tissue and the umbilical cord indicates SARS-CoV­2 vertical transmission.

[Routine high-throughput targeted sequencing of lymphoproliferative diseases : Clinical utility and challenges]. / Routinemäßige zielgerichtete Hochdurchsatzsequenzierung von lymphoproliferativen Erkrankungen : Klinischer Nutzen und Herausforderungen.

In contrast to other tumour entities such as lung carcinoma, melanoma or gynaecological and gastrointestinal tumours, the routine application of mutation analyses using high-throughput sequencing via next-generation sequencing (NGS) has not yet been widely established in haematopathology, especially not in lymphomas.Here we describe our experience with the use and routine implementation of a lymphoma NGS panel primarily developed for research purposes.In addition to a discussion of the steps necessary for transferring such a panel into the routine framework of an accredited institute, we show by the comprehensive workup of 80 investigations and the presentation of several case studies how the panel was able to guide us to the correct diagnosis and how it also provided clinicians with indications for possible tailored therapy options.Even if NGS does not (yet) have to be routinely applied in lymphoma diagnostics for every case, a respectively dedicated NGS panel offers the advantage of having an additional option in the case of difficult differential diagnostic considerations or uncertainties as well as at the request of the treating oncologist to identify potential targets for tailored treatment of the patients.

[Ectopic thymic tissue and ectopic thymic tumors]. / Ektopien des Thymus und ektope Thymustumoren.

Ectopic thymic tissue outside its core position in the antero-superior mediastinum is quite common owing to the complexity of embryonal thymus development, whereby reported prevalence values (1 to 90%) are heavily dependent on the method of investigation and the intensity of the workup. The debated prevalence and relevance of ectopic thymic tissue and its accessibility underlie the ongoing discussion whether modern, minimally invasive thymectomy strategies can match the proven benefit of the radical transsternal thymectomy procedure for the treatment of Myasthenia gravis. In this context, the following article covers the etiology, prevalence, and location of normal-looking, reactive, and neoplastic ectopic thymic tissue. Furthermore, ectopic tissues and tumors inside or adjacent to the thymus are mentioned.

The immune system and cancer evasion strategies: therapeutic concepts.

The complicated interplay between cancer and the host immune system has been studied for decades. New insights into the human immune system as well as the mechanisms by which tumours evade immune control have led to the new and innovative therapeutic strategies that are considered amongst the medical breakthroughs of the last few years. Here, we will review the current understanding of cancer immunology in general, including immune surveillance and immunoediting, with a detailed look at immune cells (T cells, B cells, natural killer cells, macrophages and dendritic cells), immune checkpoints and regulators, sialic acid-binding immunoglobulin-like lectins (Siglecs) and other mechanisms. We will also present examples of new immune therapies able to reverse immune evasion strategies of tumour cells. Finally, we will focus on therapies that are already used in daily oncological practice such as the blockade of immune checkpoints cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed death-1 (PD-1) in patients with metastatic melanoma or advanced lung cancer, or therapies currently being tested in clinical trials such as adoptive T-cell transfer.

[Non-neoplastic lesions of the mediastinum]. / Nichtneoplastische Läsionen des Mediastinums.

The mediastinum is a complex body region of limited space but containing numerous organs of different embryonic origins. A variety of lesions that are difficult to distinguish from each other can occur here. Non-neoplastic lesions of the mediastinum represent important differential diagnostic pitfalls to mediastinal tumors, clinically, radiologically and histopathologically. It is important to bear these lesions in mind and to adequately verify or exclude them before starting further differential diagnostic considerations on mediastinal neoplasms. The most common non-neoplastic lesions in this region include cysts and lymphadenopathies. Mediastinal cysts result from abnormal events in the branching of the tracheobronchial tree, the pharyngeal pouches, the primary intestines, the pleuropericardial membranes and the brain meninges or are complications of inflammatory and hydrostatic processes. The histogenesis of the lining epithelium and the cyst wall structure are decisive for the exact classification. The histopathologically most prevalent patterns of mediastinal lymphadenopathies are those accompanied by increased histiocytes and Castleman's disease. Sclerosis is a non-specific reaction pattern of the mediastinum and can be associated with many processes; therefore, when establishing the diagnosis of sclerosing mediastinitis, several differential diagnoses have to be excluded. Simple thymic hyperplasia can be accompanied by considerable increase in organ size with severe local symptoms, while follicular thymic hyperplasia is often associated with myasthenia gravis and represents the most common findings in non-thymoma thymectomy specimens.

Development of an Epstein-Barr virus-associated lymphoproliferative disorder in a patient treated with azacitidine for chronic myelomonocytic leukaemia.

Some chemotherapeutic agents can cause iatrogenic lymphoproliferative disorders. In analogy to what has been observed with other nucleoside analogues such as cladribine and fludarabine, we document the first case of an Epstein-Barr virus-positive, iatrogenic immunodeficiency-associated, lymphoproliferative disease, formally resembling polymorphic post-transplant lymphoproliferative disease in a patient treated with azacitidine (Vidaza) for chronic myelomonocytic leukaemia (CMML). A 78-year-old female patient was diagnosed with CMML in January 2012, and treatment with azacitidine was initiated, which lasted for five cycles from February until June 2012. The patient was hospitalized in June 2012 under the suspicion of pneumonia. Transformation of the CMML was suspected at that time too. During hospitalization, a generalized enlargement of the lymph nodes and the spleen was noticed. The patient rapidly deteriorated and finally died of respiratory insufficiency. At autopsy, an Epstein-Barr virus-associated lymphoproliferative disorder, resembling polymorphic post-transplant lymphoproliferative disease with involvement of the lymph nodes, the spleen and the lung and causing necrotizing pneumonia, was diagnosed. Diagnostic criteria for diffuse large B-cell lymphoma or infectious mononucleosis-like lymphoproliferative disease were not met. This is the first documented case of an azacitidine-associated lymphoproliferative disease, raising awareness for possible not yet known side effects of this drug, which should be kept in mind by oncologists and pathologists.

PIM kinases are progression markers and emerging therapeutic targets in diffuse large B-cell lymphoma.

BACKGROUND: PIM serine/threonine kinases are often highly expressed in haematological malignancies. We have shown that PIM inhibitors reduced the survival and migration of leukaemic cells. Here, we investigated PIM kinases in diffuse large B-cell lymphoma (DLBCL) biopsy samples and DLBCL cell lines. METHODS: Immunohistochemical staining for PIM kinases and CXCR4 was performed on tissue microarrays from a cohort of 101 DLBCL cases, and the effects of PIM inhibitors on the survival and migration of DLBCL cell lines were determined. RESULTS: PIM1 expression significantly correlated with the activation of signal transducer and activator of transcription (STAT) 3 and 5, P-glycoprotein expression, CXCR4-S339 phosphorylation, and cell proliferation. Whereas most cases exhibited cytoplasmic or cytoplasmic and nuclear PIM1 and PIM2 expression, 12 cases (10 of the non-germinal centre DLBCL type) expressed PIM1 predominately in the nucleus. Interestingly, nuclear expression of PIM1 significantly correlated with disease stage. Exposure of DLBCL cell lines to PIM inhibitors modestly impaired cellular proliferation and CXCR4-mediated migration. CONCLUSION: This work demonstrates that PIM expression in DLBCL is associated with activation of the JAK/STAT signalling pathway and with the proliferative activity. The correlation of nuclear PIM1 expression with disease stage and the modest response to small-molecule inhibitors suggests that PIM kinases are progression markers rather than primary therapeutic targets in DLBCL.

[Diagnosis and grading of cervical intraepithelial neoplasias]. / Diagnose und Graduierung zervikaler intraepithelialer Neoplasien.

Diagnosing and grading of cervical intraepithelial neoplasias (CIN) are part of the routine practice of pathologists. However, discriminating between reactive changes and CIN1 and determining the different degrees of CIN may be challenging. Aim of this study was the evaluation of the proliferation markers Ki-67 and Mcm2 as well as p16 for their potential to aid in the assessment of CIN. 297 samples of normal epithelium, CIN1, CIN2, and CIN3 were assessed for expression of the above mentioned markers using tissue microarrays. There was an increase in the expression of Ki67 and Mcm2 from normal epithelium, CIN1, CIN2 to CIN3 (p<0.001 for both markers). Ki-67 was the most useful marker in differentiating between normal epithelium and CIN1. The number of p16-positive cases was 7% in CIN1, 46% in CIN2 and 86% in CIN3. There were no p16-positive cases in the group with normal epithelium. In order to grade CIN1 vs. CIN2 a combination of Ki-67 and p16 was helpful. Cases with a proliferation rate of <25% assessed with Ki-67 were most likely CIN1 (sensitivity 91.7%, specificity: 54.3%, positive predictive value: 73.3%, negative predictive value 82.6%). P16 was the most helpful marker in distinguishing between CIN2 and CIN 3 as p16 negative cases were more likely to belong into the CIN2 category. In summary, the histopathological assessment of cervical biopsies is based on H&E-stained slides. However, Ki-67 and p16 can be helpful in diagnosing and grading cervical intraepithelial neoplasia.

[Normal bone marrow and common reactive alterations]. / Normales Knochenmark und häufige reaktive Veränderungen.

Histological examination of bone marrow biopsies is an important and powerful diagnostic tool to assess various hematological and non-hematological disorders. Morphological examination of such biopsies requires knowledge of the composition of normal bone marrow and its variations, such as age-related changes. Diagnostic problems may arise due to poor specimen quality, insufficient sections or stainings and insufficient experience with reactive bone marrow changes which occasionally resemble neoplastic disorders. Reactive bone marrow processes can affect one or more hematopoietic cell lines, lead to disruption of the normal architecture and specifically affect the bone marrow stroma. Optimal bone marrow diagnosis requires adequately stained slides and, when needed, immunophenotyping and molecular examinations. Furthermore, rather than biopsy interpretation of other organs, pathologists routinely need clinical history information for correct interpretation and diagnosis of bone marrow changes. In this article, the normal features of bone marrow as well as the most frequent reactive bone marrow alterations are described.

[Myositis as a post-acute sequela of COVID-19 disease? : Even in times of the pandemic, muscle biopsies can only be assessed in the context of accurate clinical information]. / Myositis als postakute Folge einer COVID-19-Erkrankung? : Auch in Zeiten der Pandemie können Muskelbiopsien oft nur im Kontext einer genauen Weitergabe klinischer Informationen beurteilt werden.

A case of a patient suffering from COVID-19 with suspected associated myositis is reported, in which the initially limited information about the history and disease course led to difficulties in establishing a reasonable diagnosis. Through inquiry, further data could be collected, so that the diagnosis of an infection-associated thrombotic microangiopathy in the context of a Morganella morganii myositis could be made. This patient study shows that even in times of the omnipresent pandemic and despite the context of a positive COVID-19 test result, differential diagnoses and the integrative clinicopathologic approach in interpreting muscle biopsy findings should not be neglected.

[Clonal relationship of Hodgkin lymphoma and its recurrence]. / Klonale Verwandtschaft von Hodgkin-Lymphomen und deren Rezidiven.

In this study, we investigated whether recurrences of classical Hodgkin's lymphoma (HL) are true relapses arising from the primary tumour or clonally unrelated secondary neoplasias. Formalin-fixed, paraffin-embedded tissue specimens of eleven patients with recurrent HL were analyzed. Hodgkin and Reed-Sternberg cells were microdissected after immunohistochemical staining for CD30 using laser-capture technique. Immunoglobulin heavy chain (IgH) gene fragment lengths were analyzed applying consensus FR3 and J primers. Two early relapses after the first HL diagnosis were clonally related to the initial tumour, while three of four early recurrences after a first or second relapse were not. Three patients presenting with late relapses had clonally unrelated neoplasms. Therefore, we conclude that recurrent HL may represent a novel neoplasm, a finding which might play a role in clinical decision-making.

Patterns of liver infiltration in lymphoproliferative disease.

AIMS: Liver involvement is a common finding in patients suffering from lymphoproliferative disease, and histopathological patterns of infiltration vary according to lymphoma subtype. Data correlating the form of liver involvement with distinct lymphoma subtypes is, however, scarce. The aim was to review 89 liver biopsies diagnosed with lymphoma infiltration and evaluate the infiltration patterns. METHODS AND RESULTS: In equivocal cases, additional immunohistochemical and molecular pathology analyses were performed to differentiate between neoplastic and reactive cell infiltrates and to classify the lymphoma subtypes. Diffuse large B-cell lymphoma (DLBCL), chronic lymphocytic leukaemia (CLL), Hodgkin's lymphoma (HL) and Burkitt lymphoma (BL) were the most prevalent subtypes in our series, which included 14 different lymphoma entities in total. Whereas DLBCL and BL predominantly demonstrated tumour nodules deranging the normal hepatic architecture, CLL and HL mostly showed infiltration of the portal fields. Interestingly, distinct lymphoma entities, particularly marginal zone B-cell lymphomas (MZL) and HL, commonly revealed lympho-epithelial lesions of bile ducts, which were observed in 10% of all investigated cases. Four cases, initially interpreted as T-cell lymphomas, proved to be reactive T-cell lesions. CONCLUSIONS: Distinct lymphoma subtypes show characteristic patterns of liver infiltration. Additional molecular analyses can support diagnosis by verification of clonality or detection of characteristic genetic aberrations.

[Rupture of the spleen. Clinicopathological correlations and diagnostic procedures]. / Milzruptur. Klinisch-pathologische Zusammenhänge und Diagnostik.

Though rare, splenic rupture is the most common indication for splenectomy. In the vast majority of cases ruptures are clearly related to trauma (traumatic ruptures); in other cases there is a pre-existing disease affecting the spleen (pathologic ruptures); and in a minority of patients no obvious reason can be identified (spontaneous ruptures). In approximately 10% of cases an iatrogenic cause, in the broadest sense (including side effects of drugs), and relevant histological findings (approximately half of which will be unexpected) can be anticipated. Knowledge of pathophysiological aspects of splenic rupture and assessment of simple macroscopic findings such as splenic dimensions and weight, and information on macroscopically visible lesions are of key diagnostic importance, as is accurate microscopic examination with targeted histological pattern analysis, supplemented as appropriate by histo- and immunohistochemical studies on adequately prepared material.

High-throughput sequencing of nodal marginal zone lymphomas identifies recurrent BRAF mutations.

Nodal marginal zone lymphoma (NMZL) is a rare small B-cell lymphoma lacking disease-defining phenotype and precise diagnostic markers. To better understand the mutational landscape of NMZL, particularly in comparison to other nodal small B-cell lymphomas, we performed whole-exome sequencing, targeted high-throughput sequencing, and array-comparative genomic hybridization on a retrospective series. Our study identified for the first time recurrent, diagnostically useful, and potentially therapeutically relevant BRAF mutations in NMZL. Sets of somatic mutations that could help to discriminate NMZL from other closely related small B-cell lymphomas were uncovered and tested on unclassifiable small B-cell lymphoma cases, in which clinical, morphological, and phenotypical features were equivocal. Application of targeted gene panel sequencing gave at many occasions valuable clues for more specific classification.

Absence of specific alternatively spliced exon of CD44 in macrophages prevents colitis.

CD44 is a transmembrane molecule appearing in numerous isoforms generated by insertions of alternatively spliced variant exons (CD44v) and having various binding partners. CD44v7 on T cells was proposed to promote colitis by preventing T-cell apoptosis. Here we demonstrate that Cd44v7-deficient T cells - like Cd44 wild-type (Cd44WT) T cells - provoked disease in two different colitis models: the model induced by CD4+CD45RBhigh T-cell transfer into Rag2-deficient mice and a new model based on ovalbumin (OVA)-specific T-cell transfer into Rag-sufficient, OVA-challenged mice. In contrast, CD44v7 absence on macrophages in recipient mice prevented colitis. Prevention was associated with the downregulation of signal transducer and activator of transcription 3 (STAT3)-activating and Foxp3-counteracting interleukin-6 (IL-6), lower numbers of phospho-STAT3-containing lymphocytes, and higher Foxp3+ T-cell counts in the colon. Consequently, the protected colons showed lower IL-12, IL-1ß expression, and decreased interferon-γ levels. Importantly, stimulation of T cells by Cd44v7-deficient macrophages induced upregulation of Foxp3 in vitro, while cotransfer of Cd44WT macrophages into Cd44v7-deficient mice reduced Foxp3+ T-cell counts and caused colitis. Accordingly, the CD44v7 ligand osteopontin, whose levels were elevated in Crohn's disease, specifically induced IL-6 in human monocytes, a cytokine also increased in these patients. We suggest macrophage-specific targeting of the CD44v7 pathway as a novel therapeutic option for Crohn's disease.

Concordant bone marrow involvement of diffuse large B-cell lymphoma represents a distinct clinical and biological entity in the era of immunotherapy.

In diffuse large B-cell lymphoma (DLBCL), the clinical and biological significance of concordant and discordant bone marrow (BM) involvement have not been well investigated. We evaluated 712 de novo DLBCL patients with front-line rituximab-containing treatment, including 263 patients with positive and 449 with negative BM status. Compared with negative BM disease, concordant BM adversely impacted overall and progression-free survival, independent of the International Prognostic Index (IPI) and cell-of-origin classification. Once BM is concordantly involved, poor prognosis was not associated with the extent of BM involvement. Conversely, patients with discordant BM showed favorable overall survival similar to stage I-II DLBCL. A BM-adjusted IPI, using three parameters: concordant BM involvement, age >60 years, and performance status >1, improves the risk stratification for DLBCL with positive BM. Intensive immunochemotherapy seemingly rendered survival benefit for patients with concordant BM, as did rituximab maintenance for the discordant BM group. Frequently revealing adverse clinical and molecular characteristics, patients with concordant BM demonstrated gene expression signatures relevant to tumor cell proliferation, migration and immune escape. In conclusion, clinical and biological heterogeneity is seen in DLBCL with positive BM but concordant BM involvement represents a distinct subset with unfavorable gene signatures, high-risk clinicopathologic features and poor prognosis.

Expression and prognostic significance of Tetranectin in invasive and non-invasive bladder cancer.

Tetranectin (TN) is a plasminogen kringle-4 binding protein that can be detected in the plasma and the extracellular matrix. In malignancies, TN is thought to enhance proteolytic processes enabling tumor cells to invade and metastasize. So far, TN expression has not been described in transitional cell bladder cancer (TCC), and there is no information on the prognostic significance of its in situ expression. TN expression was studied in 99 TCC patients diagnosed between 1994 and 1997. Immunohistochemistry was performed on a tissue microarray using a monoclonal antibody against TN (clone 11F1). Within the mean follow-up period of 60 months, pTa and pT2-4 TCC patients with stainable TN in the tumor stroma had a significant shorter recurrence-free survival and higher risk of recurrence compared to those without stainable TN (p = 0.0002 for both). TN expression in the tumor cells did not influence recurrence-free survival. In conclusion, TN is expressed in a subgroup of bladder cancer patients with a higher risk of recurrence who may take benefit from a closer follow-up.

Phosphorylated CXCR4 expression has a positive prognostic impact in colorectal cancer.

BACKGROUND: The CXCL12-CXCR4 chemokine axis plays an important role in cell trafficking as well as in tumor progression. In colorectal cancer (CRC), the chemokine receptor CXCR4 has been shown to be an unfavorable prognostic factor in some studies, however, the role of its activated (phosphorylated) form, pCXCR4, has not yet been evaluated. Here, we aimed to investigate the prognostic value of CXCR4 and pCXCR4 in a large cohort of CRC patients. PATIENTS AND METHODS: A tissue microarray (TMA) of 684 patient specimens of primary CRCs was analyzed by immunohistochemistry (IHC) for the expression of CXCR4 and pCXCR4 by tumor cells and tumor-infiltrating immune cells (TICs). RESULTS: The combined high expression of CXCR4 and pCXCR4 showed a favorable 5-year overall survival rate (68%; 95%CI = 59-76%) compared to tumors showing a high expression of CXCR4 only (48%; 95%CI = 41-54%). High expression of pCXCR4 was significantly associated with a favorable prognosis in a test and validation group (p = 0.015 and p = 0.0001). Moreover, we found that CRCs with a high density of pCXCR4+ tumor-infiltrating immune cells (TICs) also showed a favorable prognosis in a test and validation group (p = 0.054 and p = 0.004). Univariate Cox regression analysis for TICs revealed that a high density of pCXCR4+ TICs was a favorable prognostic marker for overall survival (HR = 0.97,95%CI = 0.96-1.00; p = 0.01). In multivariate Cox regression survival analyses a high expression of pCXCR4 in tumor cells lost its association with a better overall survival (HR = 0.99; 95%CI = 0.99-1.00, p = 0.098). CONCLUSION: Our results show that high densities of CXCR4 and pCXCR4 positive TICs are favorable prognostic factors in CRC.

Loss of PRDM1/BLIMP-1 function contributes to poor prognosis of activated B-cell-like diffuse large B-cell lymphoma.

PRDM1/BLIMP-1, a master regulator of plasma-cell differentiation, is frequently inactivated in activated B-cell-like (ABC) diffuse large B-cell lymphoma (DLBCL) patients. Little is known about its genetic aberrations and relevant clinical implications. A large series of patients with de novo DLBCL was effectively evaluated for PRDM1/BLIMP-1 deletion, mutation, and protein expression. BLIMP-1 expression was frequently associated with the ABC phenotype and plasmablastic morphologic subtype of DLBCL, yet 63% of the ABC-DLBCL patients were negative for BLIMP-1 protein expression. In these patients, loss of BLIMP-1 was associated with Myc overexpression and decreased expression of p53 pathway molecules. In addition, homozygous PRDM1 deletions and PRDM1 mutations within exons 1 and 2, which encode for domains crucial for transcriptional repression, were found to show a poor prognostic impact in patients with ABC-DLBCL but not in those with germinal center B-cell-like DLBCL (GCB-DLBCL). Gene expression profiling revealed that loss of PRDM1/BLIMP-1 expression correlated with a decreased plasma-cell differentiation signature and upregulation of genes involved in B-cell receptor signaling and tumor-cell proliferation. In conclusion, these results provide novel clinical and biological insight into the tumor-suppressive role of PRDM1/BLIMP-1 in ABC-DLBCL patients and suggest that loss of PRDM1/BLIMP-1 function contributes to the overall poor prognosis of ABC-DLBCL patients.