Welcome to the European Working Group
for Breast Screening Pathology (EWGBSP)
Self Evaluation Tool for Microinvasion in Breast Disease
This free evaluation unit consists of 50 challenging cases of in situ carcinomas of the breast with or without microinvasion.
You have two rounds to choose. We suggest doing the HE slides at first and as a second round the HE+IHC slides after several days.
You have also the choice to do the self-evaluation with a case by case feedback (suggest for beginners) or as a feedback at the end (suggested for experienced pathologists).
If you would like to repeat the morphological criteria of microinvasion, please click here.
Definition of Microinvasion:
A tumour in which the dominant lesion is in-situ carcinoma (usually extensive high nuclear grade DCIS, rarely other types of DCIS or lobular intraepithelial neoplasia) but in which there are one or more clearly separate foci of infiltration of non specialized interlobular or interductal fibrous or adipose tissue, none measuring more than 1 mm (about 2 hpf) in maximum diameter. (27,28,29). This definition has been officially reported in the TNM system as pT1mic since 1997 (fifth edition)(30). It is very restrictive and tumours fulfilling the criteria are consequently rare.
The tumour focus/foci must invade into nonspecialized interlobular or interductal stroma (extension of the lesion beyond the confines of a ductolobular unit, development of a desmoplastic stroma). The cells deemed to be invasive must be distributed in a fashion (non-organoid pattern) that does not represent tangential sectioning of a duct or a lobular structure with in-situ carcinoma. Tangentially sectioned in-situ carcinoma foci that simulate microinvasion are distributed in the specialized periductal and intralobular stroma and usually occur as compact groups of tumour cells that have a smooth border surrounded by a circumferential layer of myoepithelial cells and stroma or a thickened basement membrane. At sites of microinvasive foci, tumour cells are distributed singly or as small groups that have irregular shapes reminiscent of conventional invasive carcinoma with no particular orientation. There is complete absence of surrounding basement membrane and myoepithelial cells: immunostains are helpful in demonstrating the presence or absence of basement membrane components (laminin and collagen type IV) or myoepithelial cells (smooth-muscle actin, calponin, smooth-muscle myosin heavy chain). Detecting microinvasion can be difficult when there is a marked periductal fibrosis or inflammation because the true boundary of the specialized periductal or lobular stroma is not clear, but immunostaining for cytokeratin may be useful to confirm the presence of separate foci of neoplastic cells embedded in periductal fibrosis or inflammation."
Wells, C. A., et al. (2013). Pathology update. Quality assurance guidelines for pathology. In: European guidelines for quality assurance in breast cancer screening and diagnosis, Supplements. N. Perry, M. Broeders, C. de Wolf et al. Luxembourg, European Commission, Office for Official Publications of the European Union.
Your results are neither stored nor will be used for any other reason than your personal self-evaluation.
We wish you a nice session!
This article and self-evaluation tool is dedicated to our colleague, Dr.
Fritz Rank who was one of the first contributors to the study and passed
away before it could be completed. The authors are grateful to János Farkas,
Department of Informatics, Bács-Kiskun County Teaching Hospital for
preparing the original web surfaces used in the study and Stefan Sauer for
preparing the on-line self-assessment surface at Medical University of Graz.