MR imaging findings of low-grade serous carcinoma of the ovary: comparison with serous borderline tumor

Abstract

Purpose: To assess MR imaging findings of low-grade serous carcinoma (LGSC) of the ovary compared with those of serous borderline tumor (SBT).

Methods: Twenty-four patients with histopathologically proven 7 LGSCs and 25 SBTs who underwent preoperative MR imaging were included. We retrospectively reviewed MR images and compared MR findings between the two pathologies.

Results: The predominantly solid lesions were marginally more frequent in LGSCs than in SBTs (43% vs. 8%, p = 0.057). All predominantly cystic LGSCs were multilocular cystic lesions with mural nodules. Predominantly solid LGSCs exhibited pure solid masses in 2 of 3 and solid masses with intratumoral cysts in 1 of 3. Papillary growth pattern with internal branching was observed only in 18 of 25 SBTs. Signal intensity ratio on T2-weighted images (4.48 ± 1.55 vs. 8.40 ± 3.53, p < 0.01) and apparent diffusion coefficient (ADC) values (1.12 ± 0.21 vs. 1.73 ± 0.27 × 10^-3 mm²/s, p < 0.01) of solid components was significantly lower in LGSCs than in SBTs.

Conclusion: Compared with SBTs, lower signal intensity on T2-weighted images and lower ADC values were characteristic features of solid components in LGSCs. Papillary growth pattern with internal branching was not observed in LGSCs.

Keywords: Low-grade serous carcinoma; MRI; Ovary; Serous borderline tumor.