What is the difference between goiter and struma in a woman with subclinical hyperthyroidism and amenorrhea?

Goiter and Struma: Terminology Clarification

"Goiter" and "struma" are synonymous terms—both refer to thyroid gland enlargement, with "struma" being the Latin-derived term that is less commonly used in modern English medical practice. 1

Understanding the Terminology

• Goiter is the preferred English term for any enlargement of the thyroid gland, regardless of cause (toxic, nontoxic, nodular, or diffuse) 1

• Struma is simply the Latin word for goiter and means exactly the same thing—an enlarged thyroid gland 1

• In contemporary medical practice, "goiter" is the standard terminology in English-speaking countries, while "struma" may appear in older literature or in certain European medical contexts 1

Critical Exception: Struma Ovarii

The one important exception where "struma" has a distinct meaning is "struma ovarii"—a rare ovarian teratoma containing thyroid tissue that can cause hyperthyroidism. 2, 3

• Struma ovarii is a specialized ovarian tumor composed of more than 50% thyroid tissue and represents a completely different entity from thyroid goiter 2

• This condition can present with subclinical or overt hyperthyroidism and should be considered in women with treatment-resistant hyperthyroidism, particularly when accompanied by pelvic masses 2, 3

• In the context of your patient with subclinical hyperthyroidism and amenorrhea, struma ovarii becomes a critical differential diagnosis that must be excluded with pelvic imaging 2

Clinical Relevance to Your Patient

For a woman presenting with subclinical hyperthyroidism (TSH <0.45 mIU/L with normal free T4 and T3) and amenorrhea, the terminology distinction matters only if considering struma ovarii as a cause. 1, 2

• Standard thyroid goiter evaluation includes TSH, free T4, free T3, and thyroid ultrasound to assess for nodular disease 1

• If thyroid imaging is normal but hyperthyroidism persists, pelvic ultrasound is essential to exclude struma ovarii, especially given the amenorrhea. 2, 3

• Struma ovarii can coexist with Graves' disease, making diagnosis particularly challenging, as TSH receptor antibodies may stimulate both thyroid and ectopic ovarian thyroid tissue 4

Common Diagnostic Pitfall

Failing to consider struma ovarii in women with unexplained hyperthyroidism and gynecological symptoms (amenorrhea, pelvic mass) can lead to prolonged misdiagnosis and inappropriate treatment. 2, 3

• Struma ovarii accounts for less than 5% of ovarian teratomas but should be suspected when standard thyroid treatments fail 2

• The presence of elevated CA-125 alongside hyperthyroidism symptoms may suggest ovarian pathology requiring surgical evaluation 2