Endocrinol Metab.  2012 Sep;27(3):227-231. 10.3803/EnM.2012.27.3.227.

A Case of Incidental Struma Ovarii Confounded with the Metastasis of Papillary Thyroid Cancer

• Jung YH
• Jung SM
• Lee JM
• Jang YS
• Lee IS
• Kim JO
• Kim HS

• KMID: 2282407
• DOI: http://doi.org/10.3803/EnM.2012.27.3.227

Abstract

A focal radioactive iodine uptake in the pelvis of a patient with differentiated thyroid cancer needs differential diagnosis besides bone metastasis. Struma ovarii is a rare monodermal ovarian teratoma composed predominantly of mature thyroid tissue; 5-10% of these tumors are malignant. As diagnosis and surgery of thyroid cancer have increased recently, incidental cases of struma ovarii, after radioactive iodine treatment, were occasionally reported. Rare cases of ovary metastasis of thyroid cancer were also reported. We report a case of benign struma ovarii incidentally found in a patient with papillary thyroid cancer. The patient showed a sustained high level of thyroglobulin and focal radioactive iodine uptake in the right pelvis, confused with distant metastasis, after total thyroidectomy and radioactive iodine treatment.

Keyword

Papillary thyroid cancer; Struma ovarii; Thyroglobulin

MeSH Terms

Diagnosis, Differential
Female
Humans
Iodine
Neoplasm Metastasis
Ovary
Pelvis
Struma Ovarii
Teratoma
Thyroglobulin
Thyroid Gland
Thyroid Neoplasms
Thyroidectomy
Iodine
Thyroglobulin

Figure

• 

  Fig. 1 Histopathology of papillary thyroid cancer (A, B) and struma ovarii (C, D). Pathologic findings of left thyroid nodule (A, H&E stain, × 200) and a cervical lymph node (B, H&E stain, × 40) showed compact columnar epithelium with papillary feature, indicating papillary thyroid cancer with metastasis to regional lymph node. Right ovarian mass (C, H&E stain, × 40; D, H&E stain, × 200) showed typical thyroid follicles lined by a single layer of flat or columnar epithelium containing colloid, surrounded by ovarian stromal cells (arrowhead) and corpus albicans (arrow), indicating benign struma ovarii.

• 

  Fig. 2 The series of 131I whole-body scan (WBS). (A) Initial low-dose 131I posttreatment WBS after total thyroidectomy showed multiple 131I uptake foci in the thyroid bed and one in the right pelvis. (B) High-dose 131I post-treatment WBS after laparoscopic bilateral oophorectomy showed a weak radionuclide focus in the left paramedian pelvic area without any uptake in the thyroid bed. (C) Diagnostic WBS stimulated with the recombinant human thyroid stimulating hormone after 2 years of thyroidectomy demonstrated no abnormal uptake anymore.

• 

  Fig. 3 The positron emission tomography-computed tomography of pelvic area. There was no abnormal 2-[18F]fluoro-2-deoxy-D-glucose activity, whereas a 3.5 cm-sized atypical cystic mass (arrowheads) in the right ovary and an uterine myoma were detected.

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