Clinicopathologic and imaging features of struma ovarii: a retrospective study

Mei Chen^1,2Shusheng Liao³Youfeng Xu¹Xianwang Ye¹Xiupeng Jia^1,3Shengmin Zhang^1*

• ¹Affiliated Hospital, Ningbo University, Ningbo, China
• ²Ningbo First Hospital, Ningbo, Zhejiang Province, China
• ³First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China

Objectives: The struma ovarii (SO) is a rare disease, presenting significant challenges in achieving an accurate diagnosis. This study aims to delineate the clinicopathological and multimodal imaging characteristics of SO, enabling precise diagnosis of this entity.Methods: A retrospective analysis of the clinicopathological manifestations, laboratory examination results, and imaging data (including ultrasound and MRI) of 40 SO patients, who received treatment at the First Affiliated Hospital of Ningbo University over the period from January 2010 to February 2024. Results: The pathological results of 40 patients showed 21 pure SO, including 20 benign and one malignant; 19 patients with mixed SO, composing of 17 benign and two malignant. Three malignant cases were thyroid carcinoid. According to the ultrasound image, 40 SO patients were divided into three types. 22 cases were cystic which had mainly single room or separations; 12 cases were mainly cystic-solid mixed, which had multiple septations and hyperechoic nodules; six solid cases showed regular or irregular mass and rich blood supply. Five patients underwent contrast-enhanced ultrasound (CEUS) examination. The cystic wall and septation showed equal enhancement and slow regression. Two patients showed low enhancement in the protrusion and with slow regression. The MRI manifestations of SO are various. In this cohort, T1WI showed hypo-intensity in six cases and heterogeneity in six cases, T2WI showed hypo-intensity in two cases, heterogeneity in five cases and hyper-intensity in four cases, DWI showed hypo-intensity in two cases, heterogeneity in three cases and hyper-intensity in four cases. Conclusions: The incidence of SO is low, but there have some features in imaging. Cystic, cystic-solid or solid lesions in the appendage area, CEUS showed separations and solid component with rich blood flow and slow enhancement, MRI showed high signal on T2WI, multiple cysts and heterogeneous signal on T1WI, which were the imaging markers for SO. A comprehensive understanding of imaging manifestations can improve the radiologists to identify this disease, and providing a basis for an appropriate therapeutic regime.