A 42-year-old woman, gravida 1 para 1, was referred to our hospital on suspicion of hereditary breast and ovarian cancer syndrome (HBOC) due to her medical and family history. Genetic testing revealed a germline BRCA1 mutation. She was diagnosed with HBOC, and decided to undergo risk-reducing salpingo-oophorectomy (RRSO). There was no abnormal macroscopic finding in the pelvis and abdomen, and laparoscopic RRSO (LRRSO) was performed uneventfully. Pathological examination revealed mildly atypical epithelium with high p53 and low Ki-67 expression in fimbriae of the bilateral fallopian tubes and a diagnosis of serous tubal intraepithelial lesion (STIL).
Serous tubal intraepithelial carcinoma (STIC) is considered to be a premalignant lesion of ovarian serous carcinoma. In the present case, we found STIL, which is presumed to be a precursor lesion of STIC, in bilateral fimbrial epithelia of the fallopian tubes resected by LRRSO. Therefore, LRRSO is considered to be an effective prophylactic treatment for HBOC patients.