obsolete benign struma ovarii

Definition and Characteristics

Struma ovarii, also known as obsolete benign struma ovarii, is a rare type of ovarian tumor that is not cancerous. It is composed either exclusively or predominantly of thyroid tissue, making up more than 50% of the overall mass [3][6]. This condition most commonly occurs as part of a teratoma, which is a type of germ cell tumor that contains several different types of tissues and organs [4].

Incidence and Prevalence

Struma ovarii accounts for only a small percentage of all ovarian tumors, making up approximately 1% of all ovarian tumors and 3% of ovarian teratomas [8]. It is considered an uncommon class of ovarian tumors, with a rare occurrence rate.

Key Features

• Composed predominantly of thyroid tissue
• Often occurs as part of a teratoma
• Rare type of ovarian tumor (1% of all ovarian tumors)
• Can be associated with other types of germ cell tumors

References: [3] by K Nagai · 2017 · Cited by 11 — Struma ovarii is an ovarian tumor defined by the presence of thyroid tissue comprising >50% of the overall mass. It most commonly occurs as part of a teratoma. [4] by LM Roth · 2007 · Cited by 253 — Occasional cases of thyroid-type carcinoma may arise in the absence of detectable benign struma ovarii. [6] by K Nagai · 2017 · Cited by 11 — Struma ovarii is an ovarian tumor defined by the presence of thyroid tissue comprising >50% of the overall mass. It most commonly occurs as part of a teratoma. [8] Oct 22, 2024 — ... Struma ovarii (SO) is a rare type of ovarian tumor, comprising 1% of all ovarian tumors and 3% of ovarian teratomas [1].

Diagnostic Tests for Benign Struma Ovarii

Benign struma ovarii, a rare ovarian tumor composed of thyroid tissue, can be challenging to diagnose preoperatively. However, several diagnostic tests and imaging studies can help identify this condition.

• Ultrasound: While ultrasound is not very effective in diagnosing struma ovarii, it may show a complex adnexal mass with cystic and solid components [8].
• Computed Tomography (CT) and Magnetic Resonance Imaging (MRI): These imaging modalities can help identify the presence of thyroid tissue within the ovarian tumor, but they are not always accurate in differentiating struma ovarii from other ovarian lesions [7, 9].
• Laboratory tests: Elevated serum cancer antigen 125 (CA-125) levels have been reported in some cases of benign struma ovarii [10]. However, this is not a specific marker for the condition.
• Histopathological examination: The definitive diagnosis of struma ovarii is made by histopathological examination of the ovarian tissue after surgical removal. This involves examining the presence of thyroid follicles and other characteristic features of the tumor.

It's worth noting that preoperative radiologic imaging studies are not very effective in diagnosing struma ovarii, with only 4 out of 34 patients (11.8%) being correctly diagnosed using ultrasonography [8]. Therefore, a high index of suspicion and careful histopathological examination are essential for accurate diagnosis.

References:

[7] Dujardin MI. Diagnosis of uncomplicated teratomas using computed tomography (CT) and magnetic resonance (MR) imaging is fairly straightforward because both techniques are... (Source 7)

[8] Yoo SC. Pre-operative radiologic imaging studies such as ultrasonography was able to diagnose struma ovarii in only 4/34 (11.8%) patients. Other pre-... (Source 8)

[9] Rockson O. The diagnosis relies on histopathological examination and is infrequently made on routine investigations. (Source 9)

[10] Laboratory tests revealed a slightly elevated serum cancer antigen 125 level (56.3 ng/mL; normal level < 35 ng/mL). ... Benign struma ovarii typically have a good prognosis, and treatment necessitates surgical removal of the ovary, which is usually sufficient. ... Accurate preoperative radiological imaging diagnosis of struma ovarii is... (Source 10)

Treatment Options for Benign Struma Ovarii

For benign struma ovarii, surgical resection is the primary treatment option. However, in some cases, adjuvant treatment may be considered to manage any potential thyroid-related issues.

• Antithyroid Drugs: Medications like methimazole or propylthiouracil can be used to treat hyperthyroidism associated with struma ovarii [10].
• Surgical Removal (Oophorectomy): The primary treatment for benign struma ovarii is surgical removal of the affected ovary. In some cases, when the tumor is large or there is suspicion of malignancy, removal of both ovaries and the uterus (hysterectomy) may be necessary [10].

It's worth noting that adjuvant iodine-131 ablation with surgical extirpation has proven curative in malignant cases, but this is not typically required for benign struma ovarii [7].

The differential diagnosis of benign struma ovarii involves distinguishing it from other ovarian tumors, particularly those that are malignant in nature.

Key Points to Consider

• Histologic Features: Benign struma ovarii can be classified based on its histologic features, which may include the presence of thyroid tissue, follicles, and colloid [9].
• Clinical Presentation: The clinical presentation of benign struma ovarii is often non-specific and may mimic that of other ovarian tumors, including malignant neoplasms [4].
• **Elevated CA