MR imaging findings differentiating uterine submucosal polypoid adenomyomas from endometrial polyps

This study aimed to assess the efficacy of MRI for differentiating between uterine submucosal polypoid adenomyomas (PAs) and endometrial polyps (EPs).

MRI was used to examine 40 histopathologically confirmed benign polypoid endometrial tumors (8submucosal PAs and 32 EPs). Atypical PAs were excluded from this study. Quantitative measurements (maximum tumor diameter, maximum cyst diameter, number of cysts, and apparent diffusion coefficient values) and qualitative imaging findings (predominance of cystic or solid components as well as presence of cysts, hemorrhage, myometrial invasion, fluid-fluid level, and fibrous core) were correlated with the two pathologies.

The predominance of cystic components (37% vs 6%; p < 0.05) was more frequently observed in PAs than in EPs. The frequency of cysts (88% vs 25%; p < 0.01), hemorrhage (50% vs 9%; p < 0.05), and myometrial invasion (25% vs 0%; p < 0.05) were significantly higher in PAs than in EPs. No significant differences were observed in terms of the maximum tumor diameter, maximum cyst diameter, number of cysts, apparent diffusion coefficient values, and presence of fluid-fluid level and fibrous core between PAs and EPs.

The differences of MR findings with emphasis on cystic components and hemorrhage may be useful for differentiating between PAs and EPs.

The predominance of cystic or solid components and the presence of cysts, hemorrhage, and myometrial invasion were useful MR findings for differentiating between PAs and EPs.