Lymphatic Invasion in the Fallopian Tube is a Late Event in the Progression of Pelvic Serous Carcinoma and Correlates With Distant Metastasis.

The majority of extrauterine high-grade serous carcinomas are believed to arise in the fallopian tube as serous tubal intraepithelial carcinomas. The primary mode of metastasis is intraperitoneal, and patients usually present with peritoneal carcinomatosis. Although the tubes have a rich lymphatic network, tubal lymphatic invasion is observed in only a minority of cases. Fallopian tube sections from 222 patients with advanced stage high-grade extrauterine serous carcinoma were reviewed and lymphatic invasion within the lamina propria and myosalpinx were assessed. Seventeen patients were FIGO stage II, 162 stage III, and 43 stage IV. Tubal lymphatic invasion was identified in 44 cases (19.7%). Among the cases with lymphatic invasion, nonfimbrial lamina propria, fimbrial lamina propria, and myosalpingeal lymphatic invasion were present in 23 (52%), 21 (48%), and 21 (48%), respectively. Among cases with lymphatic invasion, 16 (36%) were FIGO stage IV, while among cases without lymphatic invasion, 27 (15%) were stage IV (P=0.0014, χ). In summary, in women with advanced stage high-grade extrauterine serous carcinoma, lymphatic invasion in the fallopian tube is uncommon, and is more than twice as likely to be associated with distant metastases as compared with those without tubal lymphatic invasion.