[Update on collaborative autopsy-based research in German pathology, neuropathology, and forensic medicine]

BACKGROUND

Autopsies are a valuable tool for understanding disease, including COVID-19.

MATERIALS AND METHODS

The German Registry of COVID-19 Autopsies (DeRegCOVID), established in April 2020, serves as the electronic backbone of the National Autopsy Network (NATON), launched in early 2022 following DEFEAT PANDEMIcs.

RESULTS

The NATON consortium's interconnected, collaborative autopsy research is enabled by an unprecedented collaboration of 138 individuals at more than 35 German university and non-university autopsy centers through which pathology, neuropathology, and forensic medicine autopsy data including data on biomaterials are collected in DeRegCOVID and tissue-based research and methods development are conducted. More than 145 publications have now emerged from participating autopsy centers, highlighting various basic science and clinical aspects of COVID-19, such as thromboembolic events, organ tropism, SARS-CoV‑2 detection methods, and infectivity of SARS-CoV-2 at autopsy.

CONCLUSIONS

Participating centers have demonstrated the high value of autopsy and autopsy-derived data and biomaterials to modern medicine. The planned long-term continuation and further development of the registry and network, as well as the open and participatory design, will allow the involvement of all interested partners.

[Pulmonary lymphangioleiomyomatosis (LAM)]

Lymphangioleiomyomatosis (LAM) is a rare lung disease that mostly occurs in female patients. A total of 200-400 people are assumed to be infected in Germany. A sporadic form and a form associated with the tuberous sclerosis complex (TSC) can be separated. Mutations of the TSC‑1 and TSC‑2 genes are relevant. Morphologically, pulmonary multicysts and marginal micronodal proliferations of LAM cells are characteristic. Combinations with renal angiomyolipoma are typical and, in cases with TSC glioma, facial angiofibroma and ungual fibroma are seen. Prognosis is favorable (10-year survival: 80%) and with the use of mTORC1 inhibitors it could be improved. Lung transplantation can be considered in some cases.

[A Rarely Differential Diagnosis of Exertional Dyspnea]

The determination of exercise-induced dyspnea is an important multifaceted task for a differential diagnosis of the pulmonologist. We are reporting the case of a 70-year old female patient at the time of the first presentation with a tumor filling almost the entire left hemithorax. Histologically a solitary pleural fibroma could be diagnosed.

Methylation of L1RE1, RARB, and RASSF1 function as possible biomarkers for the differential diagnosis of lung cancer

Background

Lung cancer is the major cause of cancer-related deaths worldwide. Differential diagnosis can be difficult, especially when only small samples are available. Epigenetic changes are frequently tissue-specific events in carcinogenesis and hence may serve as diagnostic biomarkers.

Material and methods

138 representative formalin-fixed, paraffin-embedded (FFPE) tissues (116 lung cancer cases and 22 benign controls) were used for targeted DNA methylation analysis via pyrosequencing of ten literature-derived methylation markers (APC, CDH1, CDKN2A, EFEMP1, FHIT, L1RE1, MGMT, PTEN, RARB, and RASSF1). Methylation levels were analyzed with the Classification and Regression Tree Algorithm (CART), Conditional Interference Trees (ctree) and ROC. Validation was performed with additional 27 lung cancer cases and 38 benign controls. TCGA data for 282 lung cancer cases was included in the analysis.

Results

CART and ctree analysis identified the combination of L1RE1 and RARB as well as L1RE1 and RASSF1 as independent methylation markers with high discriminative power between tumor and benign tissue (for each combination, 91% specificity and 100% sensitivity). L1RE1 methylation associated significantly with tumor type and grade (p<0.001) with highest methylation in the control group. The opposite was found for RARB (p<0.001). RASSF1 methylation increased with tumor type and grade (p<0.001) with strongest methylation in neuroendocrine tumors (NET).

Conclusion

Hypomethylation of L1RE1 is frequent in tumors compared to benign controls and associates with higher grade, whereas increasing methylation of RARB is an independent marker for tumors and higher grade. RASSF1 hypermethylation was frequent in tumors and most prominent in NET making it an auxiliary marker for separation of NSCLC and NET. L1RE1 in combination with either RARB or RASSF1 could function as biomarkers for separating lung cancer and non-cancerous tissue and could be useful for samples of limited size such as biopsies.

Idiopathic pleuroparenchymal fibroelastosis (PPFE) - A case study of a rare entity

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) was recognized as a rare new entity. We report the case of a 63 years old female suffering from progressive dyspnea and dry cough for three years. Two years before admission to our hospital, idiopathic pulmonary fibrosis (IPF) was diagnosed in another hospital and treatment with prednisolone and N-acetylcysteine (NAC) was commenced. At admission HRCT showed upper lobe dominant fibrosis and associated pleural thickening. Surgical biopsies were re-evaluated and revealed fibroelastosis with pleural thickening and a probable UIP pattern, consistent with idiopathic PPFE. Treatment with pirfenidone was initiated due to progression under prednisolone and NAC. Upper lobe predominant pleural thickening with associated subpleural fibrotic changes should raise suspicion of PPFE.

[Coronary atherosclerosis and progression to unstable plaques : Histomorphological and molecular aspects]

Atherosclerosis causes clinical symptoms through luminal narrowing by stenosis or by precipitating thrombi that obstruct blood flow to the myocardium (coronary artery disease), central nervous system (ischemic stroke) or lower extremities (peripheral vascular disease). The most common of these manifestations of atherosclerosis is coronary artery disease, clinically presenting as either stable angina or acute coronary syndromes. Atherosclerosis is a mainly lipoprotein-driven disease, which is associated with the formation of atherosclerotic plaques at specific sites of the vascular system through inflammation, necrosis, fibrosis and calcification. In most cases, plaque rupture of a so-called thin-cap fibroatheroma leads to contact of the necrotic core material of the underlying atherosclerotic plaque with blood, resulting in the formation of a thrombus with acute occlusion of the affected (coronary) artery. The atherosclerotic lesions that can cause acute coronary syndromes by formation of a thrombotic occlusion encompass (1) thin-cap fibroatheroma, (2) plaque erosion and (3) so-called calcified nodules in calcified and tortuous arteries of aged individuals. The underlying pathomechanisms remain incompletely understood so far. In this review, the mechanisms of atherosclerotic plaque initiation and progression are discussed.

MDM2 is an important prognostic and predictive factor for platin-pemetrexed therapy in malignant pleural mesotheliomas and deregulation of P14/ARF (encoded by CDKN2A) seems to contribute to an MDM2-driven inactivation of P53

Background:

Malignant pleural mesothelioma (MPM) is a highly aggressive tumour that is first-line treated with a combination of cisplatin and pemetrexed. Until now, predictive and prognostic biomarkers are lacking, making it a non-tailored therapy regimen with unknown outcome. P53 is frequently inactivated in MPM, but mutations are extremely rare. MDM2 and P14/ARF are upstream regulators of P53 that may contribute to P53 inactivation.

Methods:

A total of 72 MPM patients were investigated. MDM2 immunoexpression was assessed in 65 patients. MDM2 and P14/ARF mRNA expression was analysed in 48 patients of the overall collective. The expression results were correlated to overall survival (OS) and progression-free survival (PFS).

Results:

OS and PFS correlated highly significantly with MDM2 mRNA and protein expression, showing a dismal prognosis for patients with elevated MDM2 expression (for OS: Score (logrank) test: P⩽0.002, and for PFS: Score (logrank) test; P<0.007). MDM2 was identified as robust prognostic and predictive biomarker for MPM on the mRNA and protein level. P14/ARF mRNA expression reached no statistical significance, but Kaplan–Meier curves distinguished patients with low P14/ARF expression and hence shorter survival from patients with higher expression and prolonged survival.

Conclusions:

MDM2 is a prognostic and predictive marker for a platin–pemetrexed therapy of patients with MPMs. Downregulation of P14/ARF expression seems to contribute to MDM2-overexpression-mediated P53 inactivation in MPM patients.

HER2 expression and markers of phosphoinositide-3-kinase pathway activation define a favorable subgroup of metastatic pulmonary adenocarcinomas

OBJECTIVES

Pulmonary adenocarcinomas (ADC) can be sub-grouped based on dominant oncogenic drivers. EGFR mutations define an entity of metastatic ADC with favorable prognosis and high susceptibility to EGFR tyrosine kinase inhibition. In contrast, the clinical impact of additional ERBB family members in ADC is less defined. To this end we prospectively studied HER2 expression, gene amplification, and mutation in relation to outcome of patients with advanced or metastatic ADC.

MATERIALS AND METHODS

Diagnostic tumor biopsies from 193 sequential patients with stage III/IV ADC were prospectively studied for HER2 expression by immunohistochemistry (IHC). Cases with IHC scores 2+ or 3+ were analyzed by HER2 chromogenic in situ hybridization (CISH), and sequencing of HER2 exons 20 and 23. Additional prospectively determined biomarkers included PTEN, cMET, pAKT, and pERK expression, KRAS, EGFR, BRAF and PIK3CA mutations, and ALK fluorescence ISH (FISH).

RESULTS AND CONCLUSION

HER2-IHC was feasible in 176 (91.2%) cases. Of 53 (30%) cases with IHC scores 2+/3+, 45 (85%) could be studied by CISH and 34 (64%) by sequencing. The lower number of HER2-mutational analyses resulted from exhaustion of tumor tissue and DNA following mutational analysis of KRAS, EGFR, BRAF and PIK3CA. HER2 amplification was detected in 4 cases (2.3%), while no mutation was found. HER2 expression correlated with expression of pAKT and cMET. Expression of HER2 and pAKT was associated with favorable overall survival in stage IV disease. HER2-expressing ADC more frequently harbored KRAS mutations, while HER2 expression was absent in all 4 cases with BRAF mutation. HER2-IHC was not predictive of HER2 gene amplification or mutation, which both were rare events in prospectively studied patients with advanced or metastatic ADC. Expression of HER2 and pAKT define a population of patients with stage IV ADC with a distinct disease course, who could benefit from specifically tailored pharmacotherapies.

Efficient utilization of EBUS-TBNA samples for both diagnosis and molecular analyses

BACKGROUND

The assessment of an increasing number of molecular markers is becoming a standard requirement from endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) specimens. However, it is unclear how many needle passes should be performed and the amount of lung cancer cells that should be sent for molecular analyses. The objective of this study was to determine if it is feasible to divide the material obtained by EBUS-TBNA to allow for molecular analysis without compromising the accuracy of mediastinal staging.

OBJECTIVE

We aimed to determine if dividing EBUS-TBNA specimens has a negative impact on either histopathological diagnosis or molecular analysis.

METHODS

EBUS-TBNA was performed in 249 enlarged lymph nodes. Negative or ambiguous histopathological results were confirmed by surgical means and clinical follow-up over 6 months. The tissue obtained by EBUS-TBNA was placed onto a glass slide and divided for histopathological workup and molecular analysis. The number of passes was recorded. Both the accuracy of the mediastinal lymph node staging and the applicability of the sample division for molecular analysis were assessed.

RESULTS

Each lymph node was punctured an average of 3.18 times and division of the obtained material for diagnosis and molecular analysis was feasible in all cases. The sensitivity and accuracy of the mediastinal lymph node staging were 96.6% and 97.6%, respectively. A cytokeratin (CK)-19-mRNA concentration-based molecular test was feasible in 74.1% of cases.

CONCLUSION

Dividing EBUS-TBNA samples for both histopathological diagnosis and molecular testing is feasible and does not compromise the accuracy of mediastinal staging. This method may be an alternative to taking additional needle passes for molecular analyses.

[Diagnosis of pulmonary tuberculosis using Ziehl-Neelsen stain and polymerase chain reaction]

BACKGROUND

Definitive diagnosis of unclear pulmonary lesions is mainly based on morphological methods. In addition to a neoplasm, inflammatory reactions, in particular tuberculosis (TB), have to be considered in most cases. Therefore, the aim of this work was to determine whether established methods used in general pathology can be efficiently used with cytological material.

MATERIALS AND METHODS

An established polymerase chain reaction (PCR) protocol for the detection of Mycobacterium tuberculosis complex (Mtc) DNA in fixed specimens was conducted on fixed material available as an assay for liquid-based cytology (LBC). CytoLyt®-fixed material of 45 patients with clinically suspected TB or other mycobacteriosis were selected and were initially tested cytologically. In cases of absent tumor cells, PCR for detection of Mtc DNA and Ziehl-Neelsen stain (ZN) were performed.

RESULTS

In 9 patients (20 %), Mtc DNA was found by PCR. The following methods were used to obtain material: catheter biopsy (5), needle biopsy (2), transbronchial needle aspiration (1), and bronchoalveolar lavage (1). Cytologically an inflammatory reaction was observed in all cases. In 2 patients, a history of TB, in 2 further cases either silicosis or a posttransplant situation was known. In cases with a positive PCR, 7 patients (78 %) were positive in ZN and 3 patients (33.3 %) in TB culture (15.5 % vs. 6.7 % of the total cohort); however, the material used for investigation was not always from identical sources, respectively. In 36 out of 45 patients, both PCR and ZN were negative for the detection of Mtc DNA.

CONCLUSION

The material intended for LBC can be used for detection of TB with ZN and Mtc PCR.