Struma ovarii (SO) is a recognized, albeit infrequent, cause of ectopic thyroid hormone
secretion. Due to its rarity, only a few cases had been reported with fairly detailed
information on thyroid function test (TFT) results. Furthermore, data are limited
in the extent of local spread, surgical approach, and postoperative management. A
41-year-old woman from Libya presented with tremor, nervousness, weight loss, heat
intolerance, and palpitation. She had also complained of lower abdominal pain and
delayed periods. Two years earlier, she was diagnosed with hyperthyroidism, treated
with a 12-month course of antithyroid medications resulting in full resolution of
symptoms. Her TFTs revealed elevated serum triiodothyronine, thyroxine (T4), free
T4, and low thyroid-stimulating hormone (TSH). Pelvic ultrasonography showed a left
ovarian cystic mass and a suspicious of ectopic pregnancy was suggested. Abdominal
surgical exploration with left salpingo-oophorectomy was performed. Gross and microscopic
examinations confirmed the diagnosis of SO. Four weeks later, TFTs were repeated and
revealed a high level of serum TSH, and low total T4 and free T4 levels. L-thyroxine
replacement was started. In conclusion, Determination of the cause of thyrotoxicosis
is essential for proper management. If clinical data and initial investigations are
not consistent with common causes of hyperthyroidism, whole-body radioactive iodine
scan should be considered. The definitive treatment for patients with SO is surgical
resection via laparoscopic approach.
Key-words:
Atypical hyperthyroidism - pelvic mass - struma ovarii
