Serous Tubal Intraepithelial Lesion: A Precancerous Lesion - An Incidental Finding in Tubo-Ovarian Torsion

A BSTRACT Proliferative epithelial lesions in the fallopian tubes may be found incidentally during the microscopic examination of salpingectomy specimens. Recent evidence has clearly implicated the changes in the mucosa of the fimbrial end of the fallopian tube in its pathogenesis of high-grade serous carcinoma (HGSC). These lesions include serous tubular intraepithelial carcinoma (STIC), serous tubular intraepithelial lesion, p53 signature, and secretory cell outgrowth (SCOUT). STIC displays stratification of epithelium, hyperchromatic nuclei, increased mitotic figures, and prominent nucleoli. Immunohistochemistry staining shows aberrant p53 staining and a high Ki-67 index of >10%. Aberrant p53 expression can be either diffuse strong positivity or absent immunostaining due to non-sense mutations. The lesions which have a benign appearance with focal changes of atypia, low proliferative index, and do not satisfy the criteria of STIC on immunohistochemistry are labeled as serous tubular intraepithelial lesions.