Fallopian tube, epithelial atypia, MIB‐1 (Ki‐67) stain

Intraepithelial lesions of the fallopian tube are considered to be the precursors of most high‐grade serous ovarian and pelvic carcinomas. There is a spectrum of changes that can be observed, from simple secretory‐cell outgrowths, to benign epithelial stretches having p53 reactivity (“p53 signatures”) to atypical tubal lesions (“tubal intraepithelial lesions in transition”, TILT) Although 10‐15% of BRCA1 carriers can have incidental serous tubal intraepithelial carcinomas (STIC), this finding is very uncommon in the general population. This is a difficult case,because the findings are not fully diagnostic for STIC, but the cells have some morphologic and immunophenotypic features within the STIC precursor spectrum. Based on the p53 staining, proliferation, and morphology, this lesion falls between a p53 signature and “TILT” (or tubal epithelial atypia). Because its significance is as a precursor, and it is not considered a disease state or treatable condition, its use in a diagnostic report is not recommended (2014 WHO). (See Supplementary links for H&E stain and p53 stain slides in the Related Content section.)