Struma ovarii is a rare
neoplasm that accounts for approximately 0.3% of ovarian
tumors. Due to its ultrasound morphology, which is quite similar to that of malignant ovarian
carcinoma, most
struma ovarii cases are open operated with
laparotomy rather than laparoscopy. We present 3 cases of
struma ovarii, which were diagnosed preoperatively by imaging studies and removed by laparoscopic surgery. All patients were premenopausal women between ages 31‒50. The magnetic resonance imaging (MRI) findings were complex masses composed of multiple
cysts and solid components with T2-hypointense regions as well as multiple T1-hyperintense cystic areas, findings that are typical for
struma ovarii. A combination of plain computed tomography (CT), positron emission tomography (PET)-CT, and scintigraphy was useful for diagnosis. Laboratory examination revealed elevated serum
thyroglobulin, which led to the diagnosis of
struma ovarii. Laparoscopic surgeries were performed without rupturing the
tumors. Although it has been difficult to differentiate between
struma ovarii and malignant
tumors by conventional methods, recently MRI techniques appear make it possible to diagnose
struma ovarii preoperatively from the abovementioned imaging characteristic, together with laboratory data. As for treatment, we think laparoscopy could be successful for
struma ovarii, but the surgeon must be careful not to
rupture the
tumor intra-abdominally in order to prevent dissemination, which could lead to
malignancy.