부산대학교 도서관

Pregnancy complicated with struma ovarii is rare. We report a case of struma ovarii that enlarged during pregnancy. We also immunohistochemically investigated the expression of estrogen receptors (ER), progesterone receptors (PR), and thyroid stimulating hormone receptors (TSHR) in tumor cells to explore the mechanism of lesion enlargement.A 30-year-old woman was diagnosed with right ovarian mature teratoma 4 cm in diameter using MRI five months before pregnancy. After she became pregnant, transvaginal ultrasonography revealed that the mass size was gradually increased. MRI examination was again performed at 14 weeks of gestation, which showed enlargement of the tumor to 5.5 cm in diameter, however, there was no apparent malignant finding. The clinical diagnosis was mature teratoma or struma ovarii of the right ovary. Laparoscopy-assisted ovarian cystectomy was performed at 15 weeks of gestation, and the pathological diagnosis of the removed tumor was struma ovarii. Immunohistochemical examination of the tumor demonstrated the positive expression of PR, but the expression of ER and TSHR was negative.In the present case, the size of struma ovarii was increased during pregnancy, and this enlargement may be induced by pregnancy-related hormonal milieu via PR.