[Systemic consequences and clinical aspects of SARS-CoV-2 infection]. / Systemische Auswirkungen und klinische Aspekte der SARS-CoV-2-Infektion.

BACKGROUND: COVID-19 is considered a systemic disease. A severe course with fatal outcome is possible and unpredictable. OBJECTIVES: Which organ systems are predominantly involved? Which diseases are predisposed for a fatal course? Which organ changes are found with lethal outcome? MATERIALS AND METHODS: Data from published autopsy studies (28 cases by our group) with respect to organ changes and possible cause of death. RESULTS: The most severe alterations are found in the lungs by diffuse alveolar damage as a symptom of an acute respiratory distress syndrome (ARDS), in part with fibrosis. Thrombosis of small- to mid-sized pulmonary arteries is associated with hemorrhagic lung infarction. Frequent complications are bacterial pneumonias and less frequently fungal pneumonias by aspergillus. Pulmonary thromboembolism is found in 20-30% of lethal courses, also in the absence of deep venous thrombosis. Intestinal involvement of COVID-19 can be associated with intestinal ischemia, caused by shock or local thrombosis. In most cases, the kidneys display acute tubular injury reflecting acute renal failure, depletion of lymphocytes in the lymph nodes and spleen, and hyperplastic adrenal glands. The liver frequently reveals steatosis, liver cell necrosis, portal inflammation, and proliferation of Kupffer cells. Important preexisting diseases in autopsy studies are arterial hypertension with hypertensive and ischemic cardiomyopathy and diabetes mellitus but large population-based studies reveal increased risk of mortality only for diabetes mellitus not for arterial hypertension. CONCLUSIONS: Alterations of the pulmonary circulation with pulmonary arterial thrombosis, infarction, and bacterial pneumonia are important and often lethal complications of COVID-19-associated ARDS. Findings from autopsy studies have influenced therapy and prophylaxis.

Cryptogenic multifocal ulcerous stenosing enteritis (CMUSE), and neuromuscular and vascular hamartoma (NMVH): two sides of the same coin?

Multifocal stenosing enteritis, not related to Crohn's disease or drug intake, has been described under two different terms: "cryptogenic multifocal ulcerous stenosing enteritis" (CMUSE) and "neuromuscular and vascular hamartoma" (NMVH). We present three new cases of this condition and argue that the two terms reflect the same disease entity. Although etiology and pathogenesis of the disease remain largely unclear, obliterative vascular changes may play an important role.

Microsatellite instability in colorectal cancer: clinicopathological significance.

Although often viewed as a single disease, colorectal cancer more accurately represents a constellation of heterogeneous subtypes that result from different combinations of genetic events and epigenetic alterations. Chromosomal instability (CIN), microsatellite instability (MSI) and CpG island methylator phenotype (CIMP) have been identified as the three major molecular characteristics, which interact with other significant mutations, such as mutations in the KRAS and BRAF genes. High-level MSI (MSI-H) is of eminent clinical importance. It is the seminal molecular feature for the identification of individuals with Lynch syndrome, but it may also occur in sporadic cancers with CIMP phenotype, which arise from serrated precursor lesions. MSI-H status is a marker of favorable prognosis and may be used for outcome prediction, that is, molecular grading. Among others, mucinous and medullary histology, signet-ring cell differentiation, and a marked anti-tumoral immune response are histological features suggesting MSI. Universal tumor testing is recommended and may be performed using immunohistochemistry (mismatch repair protein expression) or molecular analysis, as has recently been recommended by an international task force. In this review, we consider in detail the molecular pathogenesis of colorectal cancer, focusing on the diagnosis of MSI in both hereditary and sporadic tumors.

Comparison of the Idylla™ MSI assay with the Promega™ MSI Analysis System and immunohistochemistry on formalin-fixed paraffin-embedded tissue of endometrial carcinoma: results from an international, multicenter study.

Determination of microsatellite instability (MSI) and mismatch repair deficiency (MMRD), respectively, in endometrial carcinomas (ECs) is important for diagnostic and prognostic purposes, identification of Lynch syndrome carriers, and selection of patients for immunotherapy. The Idylla™ MSI assay is fully automated, does not require non-tumoral tissue, and can be performed in about 150 min. Two hundred forty-two formalin-fixed paraffin-embedded (FFPE) EC samples from 7 international centers were tested by the Idylla™ MSI assay and compared to the Promega™ MSI Analysis System and immunohistochemistry (IHC) for MMR proteins. The cases were selected with an enrichment of MSI EC to around 40%. Concordance was 87.5% between the Idylla™ MSI assay and IHC and 88.58% between IHC and Promega™ MSI assay. Concordance between Idylla™ and Promega™ MSI assays was 89.91%. Discordant results occurred more frequently in cases with MSH6 or PMS2 deficiency. Invalid cases occurred with the three techniques (IHC, 7.00%; Promega™ MSI assay, 5.37%; and Idylla™ MSI assay, 2.47%). The concordance rate between Idylla™ MSI assay and the other 2 methods increased to 88.83% for IHC and to 91.22% for the Promega™ MSI assay when the cutoff of instability in the scoring system was moved from 0.5 to 0.3. The Idylla™ MSI assay is a rapid and highly concordant test for MSI in EC. Modification of the Idylla™ scoring system could increase the sensitivity and specificity of the MSI assay for EC analysis.

COVID-19 autopsies: Procedure, technical aspects and cause of fatal course. Experiences from a single-center.

Autopsies on COVID-19 have provided deep insights into a novel disease with unpredictable and potentially fatal outcome. A standardized autopsy procedure preferably with an in-situ technique and systematic tissue processing is important. Strict safety measures include personal protective equipment with a standardized protocol for dressing and undressing, usage of FFP-3 masks and minimization of aerosol production. The use of an airborne infection isolation (AIIR) room is preferred. Viral RNA analysis using swabs from throat, both lungs and other organs provides information on cross-organ viral dynamics. To correctly determine the full extent of pathological organ changes an adequate processing procedure is of the utmost importance. Systematic dissection and processing of the lungs revealed pulmonary infarction caused by thrombosis and thromboembolism and bacterial bronchopneumonia as the most frequent cause of death. Fungal pneumonia (aspergillus) was found in one case. The quality of the tissue was sufficient for histopathological and immunohistochemistry analyses in all cases. Viral RNA from throat or lung swabs was detectable post mortem in 89 % of the cases and could also be detected from paraffin-embedded tissue by real-time PCR. Complete COVID-19 autopsies including extensive histopathological studies and viral RNA analysis require approximately three times more human and technical resources and time compared to standard non-COVID autopsies. Autopsies on COVID-19 are feasible, present a manageable risk, while following a strict protocol, and provide novel insights into disease pathogenesis and the clinician with important feedback.

Patterns of Recurrence after Neoadjuvant Therapy in Early Breast Cancer, according to the Residual Cancer Burden Index and Reductions in Neoadjuvant Treatment Intensity.

BACKGROUND: The prognostic performance of the residual cancer burden (RCB) score is a promising tool for breast cancer patients undergoing neoadjuvant therapy. We independently evaluated the prognostic value of RCB scores in an extended validation cohort. Additionally, we analyzed the association between chemotherapy dose reduction and RCB scores. METHODS: In this extended validation study, 367 breast cancer patients with available RCB scores were followed up for recurrence-free survival (RFS), distant disease-free survival (DDFS), and overall survival (OS). We also computed standardized cumulative doses of anthracyclines and taxanes (A/Ts) to investigate a potential interaction between neoadjuvant chemotherapy dose reduction and RCB scores. RESULTS: Higher RCB scores were consistently associated with adverse clinical outcomes across different molecular subtypes (HR for RFS = 1.60, 95% CI 1.33-1.93, p < 0.0001; HR for DDFS = 1.70, 95% CI 1.39-2.05, p < 0.0001; HR for OS = 1.67, 95% CI 1.34-2.08, p < 0.0001). The adverse impact prevailed throughout 5 years of follow-up, with a peak for relapse risk between 1-2 years after surgery. Clinical outcomes of patients with RCB class 1 did not differ substantially at 5 years compared to RCB class 0. A total of 180 patients (49.1%) underwent dose reduction of neoadjuvant A/T chemotherapy. We observed a statistically significant interaction between dose reduction and higher RCB scores (interaction p-value = 0.042). CONCLUSION: Our results confirm RCB score as a prognostic marker for RFS, DDFS, and OS independent of the molecular subtype. Importantly, we show that lower doses of cumulative neoadjuvant A/T were associated with higher RCB scores in patients who required a dose reduction.