Lobular neoplasia and invasive lobular breast cancer: Inter-observer agreement for histological grading and subclassification

• Published in: Pathology, research and practice research and practice, 2019-11, Vol.215 (11), p.152611-152611, Article 152611
• Main Authors: Schaumann, Nora, Raap, Mieke, Hinze, Laura, Rieger, Luisa, Schürch, Christian M., Antonopoulos, Wiebke, Avril, Stefanie, Krech, Till, Dämmrich, Maximilian, Kayser, Gian, Puls, Florian, Länger, Florian, Tinguely, Marianne, Kreipe, Hans, Christgen, Matthias
• Format: Article
• Language: English
• Subjects: Biomarkers, Tumor - analysis; Breast Carcinoma In Situ - classification; Breast Carcinoma In Situ - pathology; Breast Neoplasms - classification; Breast Neoplasms - pathology; Carcinoma, Lobular - classification; Carcinoma, Lobular - pathology; Cell and Molecular Biology; Cell- och molekylärbiologi; Female; Humans; Inter-observer agreement; Invasive lobular breast cancer; Ki67; Lobular neoplasia; Mammary gland; Neoplasm Grading - methods; Neoplasm Grading - standards; Observer Variation
• ISSN: 0344-0338; 1618-0631
• DOI: 10.1016/j.prp.2019.152611

Lobular neoplasia (LN), invasive lobular breast cancer (ILBC) and related pleomorphic variants represent a distinct group of neoplastic mammary gland lesions. This study assessed the inter-observer agreement of histological grading in a series of ILBC and LN. 54 cases (36x ILBC, 18x LN) were evaluated by 17 observers. 3978 classification calls on various histological features, including nuclear grade, proliferative activity (Ki67 immunohistochemistry, categorical scoring), histological grade and pleomorphism were obtained. Pairwise Cohen’s kappa values were calculated and compared between various features and different observer subsets with variable histomorphological experience. In ILBC, pairwise inter-observer agreement for histological grade ranged from poor to almost perfect concordance and was higher in advanced and experienced histopathologists compared with beginners (P