A 42-year-old woman comes to the physician with a 6-month history of breast tenderness and menstrual irregularities. She also reports hot flashes and unintentional weight loss for the past few months. Physical examination shows no abnormalities. An ultrasound of the pelvis shows a right adnexal mass. TSH is low and a urine pregnancy test is negative. Pelvic ultrasound reveals a 6-cm right ovarian mass. The mass is surgically removed, and gross examination of the specimen shows a cystic lesion with an oily substance. Which of the following cell types is the most likely source of the neoplasm in this patient?

Question

A 42-year-old woman comes to the physician with a 6-month history of breast tenderness and menstrual irregularities. She also reports hot flashes and unintentional weight loss for the past few months. Physical examination shows no abnormalities. An ultrasound of the pelvis shows a right adnexal mass. TSH is low and a urine pregnancy test is negative.  Pelvic ultrasound reveals a 6-cm right ovarian mass.  The mass is surgically removed, and gross examination of the specimen shows a cystic lesion with an oily substance.  Which of the following cell types is the most likely source of the neoplasm in this patient?

Quizplus · Accepted Answer

Eductional Objective: Struma ovarii is an ovarian germ cell tumor composed of >50% mature thyroid tissue that can secrete thyroid hormone.  Therefore, struma ovarii can be a rare cause of thyrotoxicosis (eg, weight loss, irregular menses, low TSH level).

A 42-Year-Old Woman Comes to the Physician with a 6-Month