WSI validation studies in breast and gynecological pathology

In the last two decades, there has been marked development in virtual slide technology as well as its application in various subspecialties of pathology. In particular, there have been several studies examining the utility of whole slide imaging (WSI) in breast and gynecological pathology. The aim of this systematic review is to analyse published evidence regarding validation studies of WSI applied specifically to the female genital tract and breast pathology.

A systematic search was carried out in Pubmed and Embase databases and studies dealing with the validation of a WSI system for breast and gynaecological pathology. The topics evaluated concerned expertise of engaged pathologists, varied specimens, scanners, washout period, experience viewing WSI, and diagnostic concordance of WSI to traditional light microscopic diagnoses.

Of 1467 publications retrieved, 23 studies were included. Most of these studies concerned breast pathology. Validation guidelines recommended by the College of American Pathologists pertaining to a dataset of at least 60 cases, washout period, and recording intra-observer variability were followed by most studies. Major challenges encountered with WSI included difficulty identifying high-grade nuclear atypia and mitotic count for borderline ovarian tumors, interpretation of squamous intraepithelial lesions in liquid-based cervical cytology, and grading breast cancer.

Published data demonstrates the value of utilizing WSI in breast and gynecological pathology. Key issues reported with WSI systems were problems related to focus, resolution and the contrast and brightness of immunohistochemical staining patterns. Grading breast cancer and mitotic count remained challenging in WSI as in conventional microscopy.