Struma ovarii and peritoneal strumosis during pregnancy

Abstract

Background: Struma ovarii is a special type of ovarian dermoid cyst and accounts for approximately 2-3 % of all dermoid tumours. Benign struma ovarii may manifest as distant metastasis, called peritoneal strumosis, which makes it biologically similar to malignancy, and has been reported in limited cases but never discovered during pregnancy.

Case presentation: We report a patient with a history of right struma ovarii cystectomy. During pregnancy, pelvic masses with non-specific clinical presentation were found again. During the caesarean section, contralateral struma ovarii with dissemination of nodules in the peritoneal cavity was found, and pathology revealed that the masses were thyroid follicle ovarian goitres. DISCUSSION AND CONCLUSIONS: Recurrent benign struma ovarii with extraovarian dissemination is a rare aggressive clinical manifestation different from malignancy. It is emphasized that adequate assessment and complete resection of suspicious masses are of great importance.

Fig. 1

Greyscale and Doppler ultrasound images of the pelvic masses in a 39-year-old pregnant woman. a shows the period of the first trimester, and the cyst content was anechoic with thick septa. b, c and d were from the third trimester. b shows a solid hypoechoic area with rich blood flow signals in the Douglas pouch (white arrow). There were two papillary projections approximately 22 mm (arrows: c) with smooth contours and no vascularization on power Doppler (d)

Fig. 2

Pictures during the operation. a was the left ovarian cyst with a smooth wall. b shows the wall of the sigmoid colon with multiple nodules that presented with a smooth surface and gelatinous composition (white arrow)

Fig. 3

Pathology examination of resected ovarian mass and pelvic nodules. Haematoxylin-eosin staining showed thyroid follicles consistent with struma ovarii. a and b show pathology examination of the left ovarian mass. c and d were from the wall of the sigmoid colon and the surface of the uterus, respectively. The teratoma contained entirely thyroid tissue (b and d) composed of follicles filled with eosinophilic colloid material and lined by a single layer of cuboidal or columnar epithelial cells with uniform bland nuclei and eosinophilic cytoplasm (a and c)