Can MRI features differentiate ovarian mucinous carcinoma from mucinous borderline tumor?

Purpose: Our purpose was to determine if MRI could be used to distinguish ovarian mucinous carcinoma (MC) from mucinous borderline tumor (MBT).

Materials and methods: This study included 63 consecutive patients with histopathologically proven ovarian mucinous neoplasms (11 MCs and 52 MBTs) who underwent preoperative contrast-enhanced MRI. MRI images were retrospectively reviewed and compared between the 2 pathologies.

Results: The maximum tumor diameters (219.7 ± 80.8 mm vs. 177.4 ± 56.5 mm, p < 0.05) and maximum mural nodule (MN) diameters (41.7 ± 33.8 mm vs. 6.6 ± 8.9 mm, p < 0.01) were significantly larger in MCs than in MBTs. MNs larger than 5 mm (82 % vs. 29 %, p < 0.01) and abnormal ascites (45 % vs. 12 %, p < 0.05) were significantly more frequent in MCs than in MBTs. Apparent diffusion coefficient (ADC) values of MN were significantly lower in MCs than in MBTs (1.20 ± 0.25 × 10^-3 mm²/s vs. 1.61 ± 0.35 × 10^-3 mm²/s, p < 0.05). No significant difference was found in number of loculi, honeycomb sign, stained glass appearance, fluid-fluid level, thickened septa larger than 5 mm, peritoneal dissemination, or T2 hypointense microcysts between MCs and MBTs. T2 hypointense microcysts were observed only in 7 MBTs (13%).

Conclusion: MRI findings of these 2 pathologies overlapped considerably. Compared with MBTs, MCs exhibited larger tumor size, larger MN size, and lower ADC values of MN, and MCs more frequently had MNs larger than 5 mm and abnormal ascites. T2 hypointense microcysts might be a specific MRI finding in MBTs.