Displaced Epithelium in Breast Pathology: A Review

Although iatrogenic displacement of epithelial cells after breast instrumentation is a well-documented phenomenon, it is usually underdiagnosed. Misinterpretation of this issue results in overtreatment of patients in some instances. Additionally, the hazard of tumor seeding and dissemination after needling is a concern to both clinicians and patients. Both issues are addressed in this narrative review. We searched PubMed for abstracts of English-language publications using keywords “needle track/tract” and “displaced epithelium/epithelial displacement/iatrogenic displacement,” which resulted in 439 records restricted to human subjects. We read all the abstracts and selected 27 manuscripts with the most relevance. There are some histopathologic features that can be useful in differentiating between epithelial displacement and real invasion/metastasis. The risk of seeding or metastasis after needling is shown to be trivial. Factors militating against the growth of dislodged cells are also discussed. Epithelial displacement is an important issue in breast pathology that should be considered in every patient with a history of breast instrumentation.