Browsing by Author "Bremmer, Felix"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Multi-Observer Study on the Assessment of Pediatric Gonadal Tumors Using Higher Harmonic Generation Microscopy as Compared to Conventional Histology
    (MDPI, 2025-05-12) Spies, Sylvia; Nazarian, Elina; Bremmer, Felix; Gonzalez, Ivan A.; Lobo, João; Reyes-Múgica, Miguel; Zambrano, Eduardo; Hulsker, Caroline C. C.; Mavinkurve-Groothuis, Annelies M. C.; de Krijger, Ronald R.; Groot, Marie Louise; Pathology and Laboratory Medicine, School of Medicine
    Background/objectives: Pediatric gonadal tumors are rare tumors, and germ cell tumors (GCTs) are the most common subgroup. GCTs are heterogeneous tumors and have different subtypes that can be either benign or malignant. Therefore, extensive sampling of the resected tumor is required to obtain an accurate diagnosis. Higher harmonic generation microscopy (HHGM) is an innovative imaging technique that enables rapid visualization of fresh tissue without the need for preparation or staining. This makes it particularly valuable for sample selection, as the tissue can be reused for further analysis. This study aims to evaluate the accuracy of pathologists detecting normal gonadal tissue, germ cell tumors, and other pediatric gonadal tumors in HHGM images. Methods: Twenty-eight samples of twenty-two patients with a germ cell tumor or other gonadal tumor were imaged with the HHG microscope and subsequently processed for histology. Overview images of the samples were made in 10 s per mm2, and high-quality images in 1 min per mm2. A multi-observer study was performed with five expert pathologists. Results: Pathologists were able to differentiate between tumor and non-tumor tissue with an accuracy of 75% (21/28) on the HHGM images versus an accuracy of 89% (25/28) on the corresponding histology. Discrepancies mainly concerned teratoma cases for HHGM as well as H&E, indicating that sampling errors of these heterogeneous tumors affected the outcomes of this study adversely. Conclusions: Although the sample size was limited by the rarity of these tumors, our data show that HHGM is a promising technique for the rapid assessment of pediatric gonadal tumor samples, particularly in evaluating their representativeness.
  • Thumbnail Image
    Item
    Unexpectedly high variability in determining tumour extent in prostatic biopsies: implications for active surveillance
    (Wiley, 2025) Bernhardt, Marit; Weinhold, Leonie; Bremmer, Felix; Chan, Emily; Cheng, Liang; Collins, Katrina; Downes, Michelle; Greenland, Nancy; Hommerding, Oliver; Iczkowski, Kenneth A.; Jufe, Laura; Kreft, Tobias; van Leenders, Geert; Oxley, Jon; Perry-Keene, Joanna; Reis, Henning; Schmid, Matthias; Tsuzuki, Toyonori; Wobker, Sara; Wiliamson, Sean R.; Kweldam, Charlotte; Kristiansen, Glen; Pathology and Laboratory Medicine, School of Medicine
    Aims: Tumour content in prostatic biopsies is an important indicator of prostate cancer volume and patient prognosis. Consequently, guidelines typically recommend reporting it as a percentage or linear length (mm). This study aimed to determine the current practices for reporting tumour content in prostatic biopsies and evaluated the consistency among pathologists in diagnosing 10 standard biopsy cases of prostate cancer to assess interobserver variability. Methods and results: A web-based survey gathered data on demographics, experience and attitudes regarding the reporting of prostate cancer and its extent in biopsies. Virtual microscopy allowed analysis of 10 biopsy cases, each consisting of a single slide of prostate cancer. Self-reports from 304 participants recruited via the International Society of Urological Pathology and the German Society of Pathology were analysed. Most participants (43.4%) reported tumour extent as percentage of the biopsy core, 37.6% reported percentages and mm and 18.3% reported mm exclusively. The methods used to determine percentages showed an unexpected spread of choices, leading to considerable variability in results. Additionally, 40.8% of participants took part in the practical segment of the survey. The reported measures of tumour extent confirmed a notable interobserver variability, which was significantly higher for reported percentages. Conclusion: A high rate of interobserver variability in reporting tumour content in prostatic biopsies was found. This matter is especially critical for patients who are candidates for active surveillance. Reporting absolute measures of tumour content has the advantage of lower variability in comparison to percentages.