MR findings of struma ovarii
Jong Chul Kim*, Sung Soo Kim, Jin Yong Park
Department of Diagnostic Radiology, Chungnam National University Hospital, 640 Dacesa-dong, Jung-ku, Taejeon 301-721, South Korea
Received 20 September 1999; accepted 1 March 2000
This study was performed to characterize MR findings of struma ovarii. In 10 patients, T1- and fast spin echo T2-weighted MR images
were obtained in the axial, coronal, and sagittal planes using 1.5 T MR units, and they were retrospectively evaluated for the site, size,
components, signal intensity, and contrast enhancement. MR images showed a unilateral complex mass with a multilobulated surface and
thickened septa, corresponding pathologically to thyroid follicles and the stroma. Cystic portions had variable signal intensities on T1- and
T2-weighted images. The contents of cystic components showing low signal intensities both on T1- and T2-weighted images were viscid
gelatinous materials (n = 4). Solid portions were relatively well-enhanced. In conclusion, struma ovarii has some characteristic MR
appearance of a multilobulated complex mass with thickened septa, multiple cysts of variable signal intensities, and enhancing solid
components. D 2000 Elsevier Science Inc. All rights reserved.
Keywords: Struma ovarii; MR images; Multilobulated; Ovary neoplasms; Ovary; Cysts; Ovary; MR
The mature cystic teratomas constitute the majority of
ovarian germ cell tumors [1,2], and thyroid tissues are
found in 5±15% of these tumors on pathologic examina-
tions [2 ±4]. Struma ovarii is a rare ovarian tumor com-
posed solely or predominantly of thyroid tissue or the
tumor in which hyperthyroidism results from the ovarian
thyroid tissue [1,2,5 ± 8]. Pure struma ovarii with micro-
scopic or macroscopic thyroid tissue constitutes 2% of all
germ cell tumors of the ovary  and 2.7% of all ovarian
teratomas . Preoperative clinical or radiologic diagnosis
of struma ovarii, however, is very difficult.
There are limited numbers of radiologic reports of
struma ovarii [2,4,7,9 ±16], and the majority of these are
case reports [2,7,11,13±15]. Even though magnetic reso-
nance (MR) imaging is known to be useful in the detection
and characterization of adnexal masses, to our knowledge,
there are only several reports concerning the MR findings
of this rare tumor [4,7,11,16]
The purpose of this study was to evaluate whether there
were any characteristic imaging findings in struma ovarii
through the retrospective analysis of MR findings.
1. Materials and methods
During the recent 11 years, 10 cases of pathologically
proven struma ovarii after salpingo-oophorectomy were
retrospectively identified in our hospital and its affiliated
hospitals by reviewing medical records.
The age of the 10 patients ranged from 37 to 73 years
(average, 51). Of the 10 patients, nine women complained
of palpable lower abdominal masses, and one woman was
admitted due to symptoms and signs of hyperthyroidism
such as facial flushing, palpitation, etc. Thyroid function
test after admission was positive in the latter patient.
GE Signa 1.5 T MR unit (General Electric Medical
Systems, Milwaukee, WI, USA) was used to obtain
T1-weighted images (TR/TEeff 410 ±660/11±17 ms), fast
spin echo T2-weighted images (TR/TE 3200±6000/85 ±
132 ms; echo train length = 8, 12) and gadolinium-
enhanced T1-weighted images in the axial, coronal, and
sagittal planes. Contrast-enhanced images were obtained
after intravenous injection of gadopentetate dimeglumine
(Magnevist, Schering, Berlin, Germany, 0.1 mmol/kg). In
3 of 10 patients, fat saturation techniques were performed
to differentiate whether hyperintense areas in the tumors
on T1-weighted images were due to hemorrhage, fat, and/
or fluid of high protein content. The sequence parameters
were as follows: section thickness = 8± 10 mm; field of
* Corresponding author. Tel.: +82-42-220-7835; fax: +82-42-253-0061.
E-mail address: email@example.com (J.C. Kim).
0899-7071/00/$ ± see front matter D 2000 Elsevier Science Inc. All rights reserved.
PII: S 0899-7071(00)00158-3
Journal of Clinical Imaging 24 (2000) 28 ±33