ObjectivePrimary fallopian tube carcinoma represents a rare entity, accounting for about 0.75%–1.2% of all gynecological malignancies. The rationale of our study is to describe the prognosis of primary fallopian tube carcinoma.MethodsWe retrospectively identified patients with FIGO stage I–IV, all histology types and grading primary fallopian tube carcinoma treated in three major oncological centers between January 2000 and March 2020. Exclusion criteria were bulky tubo-ovarian carcinomas, isolated serous tubal intraepithelial carcinoma or neoadjuvant chemotherapy.ResultsA total of 61 patients were included. The vast majority of primary fallopian tube carcinomas were serous (96.7%) and poorly differentiated (96.7%) and arose from the fimbriated end of the tube (88.5%). Larger tumor size correlated with higher probability of correct preoperative differential diagnosis of primary fallopian tube carcinoma (p=0.003). Up to 82.4% of patients with small tumors (≤15 mm) presented with high FIGO stage (≥IIA). The most common site of metastasis was pelvic peritoneum (18.8%) and among 59% of patients who underwent lymphadenectomy smaller tumors had higher rate of nodal metastasis (42.9%≤10 mm vs 27.3%>50 mm). After 46.0 months of mean follow-up there were 27 recurrences (48.2%). The most common site of relapse was diffuse peritoneal spread (18.5%). The 5-year disease-free survival was 45.2% and 5-year overall survival was 75.5%. Of note, 42.9% of patients with stage IVB survived >36 months.ConclusionPrimary fallopian tube carcinoma is a biologically distinct tumor from primary epithelial ovarian carcinoma and it is mostly located in the fimbriated end of the tube. In addition, it is characterized by a high rate of retroperitoneal dissemination even at apparently an early stage and its size does not correlate with FIGO stage at presentation.