Fallopian tube origin of supposed ovarian high‐grade serous carcinomas

INTRODUCTION: Serous carcinomas are the most frequent histologic type of ovarian and peritoneal cancers, and can also be detected in the endometrium and fallopian tubes. Serous carcinomas are usually high‐grade neoplasms when diagnosed, yet the identification of an associated precursor lesion remains challenging. Pathological examination of specimens obtained from prophylactic bilateral salpingo‐oophorectomies that were performed for patients harboring BRCA1/2 mutations suggests that high‐grade serous carcinomas may arise in the fallopian tubes rather than in the ovaries. OBJECTIVE: To investigate the presence and extent of fallopian tube involvement in cases of serous pelvic carcinomas. METHODS: Thirty‐four cases of serous pelvic carcinoma with clinical presentations suggesting an ovarian origin were analyzed retrospectively. Histologic samples of fallopian tube tissues were available for these cases and were analyzed. Probable primary site, type of tubal involvement, tissues involved in the neoplasia and vascular involvement were evaluated. RESULTS: Fallopian tube involvement was observed in 24/34 (70.6%) cases. In 4 (11.8%) of these cases, an intraepithelial neoplasia was present, and therefore these cases were hypothesized to be primary from fallopian tubes. For an additional 7/34 (20.6%) cases, a fallopian tube origin was considered a possible primary. CONCLUSIONS: Fallopian tubes can be the primary site for a subset of pelvic high‐grade serous carcinomas.