MRI can be used to differentiate between primary fallopian tube carcinoma and epithelial ovarian cancer

To investigate typical features of primary fallopian tube carcinoma (PFTC) on magnetic resonance imaging (MRI) to differentiate it from epithelial ovarian cancer (EOC).

Twenty-one patients with PFTC and 35 patients with EOC were included. The clinical and pathological features of patients were analysed. The following MRI features were compared: maximal diameter, laterality, configuration, shape, signal intensity, enhancement pattern, hydrosalpinx, intrauterine fluid accumulation, rim enhancement, and apparent diffusion coefficient (ADC) values within the solid components of tumours in PFTC and EOC.

The maximal diameter of PFTC was 4.50±2.10 cm. The shapes of PFTC were mural papillary nodules (2/21, 10%), sausage-like (8/21, 38%), nodular (3/21, 14%), or irregular (8/21, 38%). Enhancement was mild (10/21, 48%), moderate (8/21, 38%), or marked (3/21, 14%). Associated hydrosalpinx and intrauterine fluid accumulation were observed in six (29%) and three (10%) cases, respectively. Significant differences between PFTC and EOC were found in the International Federation of Gynecology and Obstetrics (FIGO) stage, maximal diameter, shape, enhancement pattern, hydrosalpinx, and intrauterine fluid accumulation (p=0.002, 0.004<0.001, <0.001, and 0.048, respectively). Rim enhancement was more prevalent, thicker, and exhibited higher continuity in PFTC than in EOC (p=0.002, <0.001, and 0.002, respectively).

Rim enhancement is a useful feature in distinguishing PFTC from EOC, particularly when continuous or seen in combination with a sausage-like shape, hydrosalpinx or intrauterine fluid accumulation. When the tumour is associated with other MRI signs, for example, (i) hydrosalpinx with mural papillary nodules or sausage-like shape with mild-to-moderate enhancement of solid components, (ii) hydrosalpinx, or (iii) intrauterine fluid accumulation, the diagnosis of PFTC should be considered.