Struma ovarii with massive ascites mimicking ovarian carcinoma treated with conservative laparoscopic surgery: a case report

Abstract

Struma ovarii is a rare taratoma that accounts for 0.5 -1% of all ovarian tumors. It is sometimes difficult to differentiate struma ovarii from ovarian carcinoma. We encountered a case of struma ovarii that was suspected to be malignant due to the accumulation of massive ascites and an elevated CA125 level. It was successfully treated with laparoscopic surgery. A 37 -yearold nulliparous woman consulted a local physician with a chief complaint of abdominal distention. Computed tomography (CT) of the abdomen revealed a pelvic tumor with a large amount of ascites. She was referred to our department. Contrastenhanced magnetic resonance imaging (MRI) and CT showed bilateral ovarian tumors with multicystic and solid components. CA125 level was markedly elevated. Two cytological examinations of ascites showed no malignant cells. Preoperatively, malignancy was strongly suspected, but considering the possibility of a benign ovarian tumor, laparoscopic surgery was scheduled. During laparoscopic surgery, 4,850 mL of ascites were aspirated, and the left adnexa was removed. Intraoperative rapid pathology suggested struma ovarii with no evidence of malignancy. Postoperative pathology showed mature teratoma and struma ovarii. Although struma ovarii is benign in 90 -95% of cases, there have been scattered case reports in which suspected malignancy led to unnecessary or excessive surgery. We propose that appropriate preoperative imaging and accurate intraoperative rapid pathology can prevent excessive surgery, conservative or laparoscopic excisions should be considered.

Struma Ovarii with Papillary Thyroid Carcinoma and Metastasis to the Appendix: A Case Report and Literature Review

“…On the basis of the aforementioned imaging features, it is not always simple to diagnose struma ovarii preoperatively; instead, a definitive diagnosis is made by postoperative pathological examination. 17 , 19 , 22 …”

“…1,14,16,18 Imaging can be helpful in the diagnosis of struma ovarii even though it is frequently challenging to distinguish it from ovarian cancer. 19 Malignant struma ovarii is shown as a mixed solid and cystic mass on ultrasound, with color Doppler imaging showing abundant and low resistance flow within the core solid component. 20 A multiloculated cystic mass with a solid component that typically exhibits strong gadolinium enhancement and fluid with varying signal intensity (giving it a "stained glass appearance") is seen on MRI.…”

“…On the basis of the aforementioned imaging features, it is not always simple to diagnose struma ovarii preoperatively; instead, a definitive diagnosis is made by postoperative pathological examination. 17,19,22 With a much higher level of specificity for the tumor marker in the postmenopausal group, 51.16% of the cases tested positive for CA125 (>35 U/mL). However, it is important to remember that this marker is raised in all malignant ovarian tumors.…”