OVERVIEW

What is a thyroid adenoma?

A thyroid adenoma is the most common benign tumor of the thyroid gland, originating from the thyroid follicular epithelium. Pathologically, it presents with a complete capsule, smooth surface, clear and neat boundaries, and is usually a single nodule within the thyroid gland, with multiple nodules being rare.

The vast majority of thyroid adenomas do not cause abnormal thyroid function. They can be monitored with follow-up and do not require immediate intervention. For adenomas that cause hyperthyroidism, treatment can be tailored to the patient's specific condition, with radioactive iodine-131 therapy generally being the first choice.

Is the incidence of thyroid adenoma high?

Among thyroid diseases, thyroid adenomas have a relatively high incidence, accounting for 60% of thyroid disorders. Thyroid adenomas can occur at any age but are most common between 15 and 40 years old. They are more prevalent in women than in men, with a male-to-female ratio of approximately 1:6.

What is a toxic thyroid adenoma (hyperfunctioning thyroid adenoma)?

The vast majority of thyroid adenomas do not cause abnormal thyroid function.

In rare cases, a thyroid adenoma may produce thyroid hormones, leading to symptoms of hyperthyroidism such as palpitations, hand tremors, excessive sweating, weight loss, and increased appetite. Such hormone-secreting adenomas are called toxic thyroid adenomas (or hyperfunctioning thyroid adenomas).

SYMPTOMS

What are the manifestations of thyroid adenoma?

• Most patients with this condition have no obvious symptoms and often discover a painless lump in the anterior neck area unintentionally or during routine physical examinations. The lump is usually solitary and moves with swallowing.

• The tumor grows slowly, but if bleeding occurs inside the tumor, its size may suddenly increase, accompanied by pain and tenderness.

• A few enlarging tumors may gradually compress surrounding tissues, causing tracheal compression and displacement. Patients may experience difficulty breathing, especially when lying flat. Thyroid adenomas behind the sternum may compress the trachea and major blood vessels, leading to breathing difficulties.

• Hyperfunctioning thyroid adenomas can cause hyperthyroidism symptoms such as palpitations, hand tremors, excessive sweating, weight loss, and increased appetite.

Can thyroid adenoma turn into cancer?

Recent research by Academician Ning Guang from Ruijin Hospital indicates that benign thyroid tumors and thyroid cancers originate from different cell types. In other words, adenomas and cancers are inherently distinct from the outset. Therefore, it can be generally concluded that a correctly diagnosed benign thyroid adenoma will not become malignant.

Thus, accurately determining whether a thyroid nodule is benign or malignant is crucial during examinations.

The majority of nodules are benign, with malignant nodules accounting for only 5%–15% or even a lower proportion of all cases.

Currently, the most fundamental and important screening method for distinguishing between benign and malignant thyroid nodules is thyroid ultrasound. Malignant nodules exhibit certain ultrasound characteristics, such as hypoechogenicity, irregular shape, indistinct margins, solid structure, rich blood supply, calcifications (especially microcalcifications), a taller-than-wide shape (aspect ratio > 1), and associated lymphadenopathy.

For nodules suspected to be malignant, further evaluation with ultrasound-guided fine-needle aspiration biopsy or close follow-up is recommended.

CAUSES

What are the causes of thyroid adenoma?

The pathogenesis of thyroid adenoma is not yet clear. Multiple factors such as gender, genetics, environment, goitrogenic factors, iodine deficiency, chemical stimulation, and endocrine changes may contribute to its occurrence.

Under what circumstances can thyroid adenoma lead to thyroid crisis?

Thyroid crisis, also known as thyrotoxic crisis, mostly occurs in patients with severe hyperthyroidism who have not received treatment or inadequate treatment. Common triggers include infection, surgery, and emotional stress.

What are the manifestations of thyroid crisis?

Main symptoms include: high fever (body temperature > 39°C), rapid pulse (> 120 beats/min), restlessness, delirium, vomiting, watery diarrhea, and profuse sweating. If not treated promptly, it can rapidly progress to coma, collapse, shock, or even death, with a mortality rate of 20%–30%.

DIAGNOSIS

How is thyroid adenoma diagnosed?

The diagnosis of thyroid adenoma is primarily based on medical history, physical examination, ultrasound, and isotope scanning:

• A painless neck mass, usually asymptomatic in the early stages, occasionally accompanied by swallowing discomfort or a choking sensation, commonly seen in middle-aged women;

• A single round nodule can be palpated within the thyroid, occasionally multiple, with a smooth surface, clear boundaries, no adhesion to the skin, and moves up and down with swallowing;

• Ultrasound can further determine the size and shape of the thyroid adenoma. It is non-invasive, simple, and relatively inexpensive, making it clinically significant for diagnosis;

• Nuclear scans often show "warm nodules," with a few cases presenting as "cold nodules" or "hot nodules." Thyroid 131 iodine uptake is generally normal;

• Thyroid function tests are mostly normal. Elevated thyroid function indicators require further examination;

• Neck X-ray: If the tumor is large, anteroposterior and lateral views may show tracheal compression or displacement, with some tumors displaying calcification;

• Thyroid lymphography;

• Thyroid fine-needle aspiration biopsy, etc.

Which diseases can thyroid adenoma be easily confused with?

Thyroid adenoma needs to be differentiated from nodular goiter, thyroid cysts, and thyroid cancer. However, it should be noted that thyroid adenoma can coexist with goiter, thyroiditis, and thyroid cancer.

Does calcification on thyroid ultrasound indicate malignancy?

Calcification refers to calcium deposition in the thyroid due to various causes. The presence of calcification does not necessarily indicate thyroid cancer.

• Generally, malignant thyroid tumors have a higher incidence of calcification, mostly microcalcifications. Typical thyroid cancer presents as "sand-like" calcifications, and ultrasound showing thyroid nodules with such calcifications is a specific sign of potential malignancy.

• Benign tumors have a lower incidence of calcification, mostly presenting as coarse or peripheral calcifications. Peripheral calcification is often considered a marker of benign thyroid tumors. Studies show that thyroid cancer is mainly associated with microcalcifications, nodular thyroid adenoma with coarse calcifications, and thyroid adenoma primarily with peripheral calcifications.

For a definitive diagnosis, a thyroid fine-needle aspiration biopsy is the preferred method. Other possible tests include thyroid function nuclear scans, neck X-rays, and thyroid lymphography.

TREATMENT

Which department should I see for thyroid adenoma?

It is recommended to first undergo an initial evaluation of the nodule's benign/malignant nature and functionality in the endocrinology department. If surgical intervention is deemed necessary, preoperative examinations and assessments (which may require multidisciplinary discussion and collaboration involving endocrinology, radiology, nuclear medicine, pathology, and thyroid/breast surgery departments) should be completed before referral to the thyroid/breast surgery department for surgical treatment.

Does thyroid adenoma require treatment?

Clinically, most non-functional thyroid adenomas can be monitored without special intervention unless the following conditions apply:

• The nodule cannot be ruled out as malignant, requiring further thyroid biopsy for diagnosis, or surgery is directly chosen if malignancy is highly suspected;
• The nodule is too large or grows rapidly, compressing normal thyroid tissue or surrounding structures (e.g., trachea, esophagus, recurrent laryngeal nerve) and causing symptoms;
• The nodule is in a special location, such as retrosternal, posing a risk of compression;
• The nodule is functional (e.g., hyperfunctioning adenoma), in which case surgery is recommended.

What if a thyroid adenoma turns cancerous?

If a thyroid adenoma shows signs of malignancy, doctors will recommend surgical removal. For patients unable to undergo surgery due to physical or other reasons, conservative treatment (medication and regular check-ups) is advised.

What are the treatment options for thyroid adenoma?

• **Medication**: Oral thyroid hormone preparations can inhibit pituitary TSH secretion, reducing TSH stimulation of the adenoma and causing it to shrink or even disappear.
• **Surgery**: In the past, single nodules were often managed conservatively with thyroid hormone or observation due to slow progression and lack of symptoms. However, given the potential for malignancy (~10%) or hyperthyroidism (~20%), surgery is now generally recommended.

Can thyroid adenoma be completely cured?

Thyroid adenoma is a common benign tumor. Surgical removal typically leads to a full cure, and postoperative thyroid hormone therapy can prevent recurrence. For patients who develop hypothyroidism, thyroid hormone replacement therapy can maintain normal bodily function. Overall, the prognosis is excellent, and rare recurrences can be treated with repeat surgery.

What preparations are needed before thyroid adenoma surgery?

• **Diet**: High-calorie, high-protein, vitamin-rich foods to improve surgical tolerance. Avoid stimulants like morphine, strong tea, alcohol, and tobacco. Fasting is required 10 hours before surgery.
• **Positioning**: To adapt to the hyperextended head/neck position during surgery, practice with a thin pillow under the shoulders for 10–30 minutes, 3 times daily, 2–3 days preoperatively.
• **Hyperthyroidism**: If present, surgery should be delayed until thyroid function normalizes to ensure safety and reduce complications.

Why is rapid pathological examination performed during thyroid adenoma surgery?

Differentiating thyroid adenoma from early-stage thyroid cancer is challenging. Frozen section pathology (a rapid diagnostic method) is used intraoperatively to detect malignancy, guiding surgical decisions. Pathology is the gold standard for diagnosis and determines the surgical approach.

What is minimally invasive surgery for thyroid adenoma?

Minimally invasive thyroid surgery (endoscopic) involves small incisions in the chest/axilla, using a flexible tube-like instrument to remove the adenoma without neck scars, ideal for patients prioritizing aesthetics.

What are the complications of thyroid adenoma surgery?

The thyroid's complex anatomy (proximity to esophagus, trachea, and vascular/nerve structures) raises risks of injury, leading to:

• Neck pain, tightness, swallowing difficulty, or voice changes.
• Severe cases: Respiratory distress, hypoparathyroidism, or (in hyperthyroid patients) life-threatening thyroid storm.

What are the signs of parathyroid injury?

Parathyroid damage (accidental removal or impaired blood supply) causes hypocalcemia, with symptoms appearing 1–3 days post-op:

• Tingling/numbness in face, lips, hands, or feet.
• Severe cases: Painful spasms, tetany, or laryngospasm risking suffocation.

Why does respiratory distress occur after thyroid adenoma surgery?

Progressive breathing difficulty (within 48 hours) may result from:

• **Bleeding**: Hematoma from slipped ligatures compressing the trachea.
• **Laryngeal edema**: Surgical or intubation irritation.
• **Tracheal collapse**: Long-standing tumor pressure weakening the trachea.
• **Bilateral recurrent laryngeal nerve damage**.

Why are sterile tracheostomy kits and gloves kept at the bedside post-op?

The thyroid’s rich blood supply (~100–150 mL/min) means rapid hemorrhage can cause life-threatening airway compression. Emergency tracheostomy kits are prepared for immediate use if swelling or breathing difficulty arises.

Is hoarseness after thyroid surgery due to nerve damage? What to note?

• **Superior laryngeal nerve damage**: Low-pitched voice or choking (especially with liquids). Eat slowly with semi-solid foods; recovery is usually spontaneous.
• **Recurrent laryngeal nerve damage (unilateral)**: Hoarseness. Rest the voice; recovery typically takes 3–6 months.
• **Bilateral damage**: Loss of voice or severe dyspnea requiring urgent tracheostomy.

Does thyroid adenoma removal affect the body long-term?

Most patients experience no major impact. Some may develop hypothyroidism, requiring lifelong levothyroxine. Other effects align with surgical complications.

How is thyroid storm treated?

• **General measures**: Cooling, IV glucose, oxygen.
• **Potassium iodide solution**: Lowers thyroid hormone levels.
• **IV hydrocortisone**.
• **Propranolol**.

Improvement usually occurs within 36–72 hours.

DIET & LIFESTYLE

What should be noted in the diet after thyroid adenoma surgery?

Six hours after the patient regains consciousness post-surgery, a small amount of warm water can be given for swallowing. If there is no discomfort such as choking or aspiration, gradually provide easily swallowed, lukewarm liquid foods, then transition to semi-liquid and soft foods. Avoid excessively hot food to prevent blood vessel dilation, which may cause bleeding and affect wound healing. If the patient experiences pain or discomfort while swallowing, small, frequent meals can be given to reduce discomfort.

What should be noted after thyroid adenoma surgery?

• Positioning: After returning to the room, the patient should lie flat with a soft pillow under the shoulders. Apply an ice pack to the wound for 24 hours to reduce bleeding. Once the patient is fully conscious and blood pressure stabilizes, a semi-reclining position is recommended to aid breathing, expectoration, and respiratory tract clearance, preventing lung infections and promoting wound healing by facilitating drainage of exudate.
• Activity: The patient may get out of bed 6–8 hours post-surgery for light activities, such as short walks or using the bathroom. Gradually increase activity levels and duration over the next 1–2 days.
• When coughing post-surgery, support the neck with hands to minimize vibration and prevent wound reopening.

What should be noted in case of parathyroid injury?

If parathyroid injury occurs, limit foods high in phosphorus, such as lean meat, milk, egg yolks, and fish (as high phosphorus levels hinder calcium absorption).
For mild symptoms, oral calcium gluconate may be given. For severe or prolonged cases, supplement with vitamin D₃ to enhance intestinal calcium absorption. Oral dihydrotachysterol oil can raise blood calcium levels and reduce neuromuscular excitability.
During a tetany episode, immediately place a tongue depressor or spoon handle between the molars to prevent tongue biting, and administer intravenous 10% calcium gluconate.

PREVENTION

Can Thyroid Adenoma Be Prevented?

Since the cause of thyroid adenoma remains unclear and may be related to factors such as autoimmunity, family genetics, and radiation exposure, it is recommended to avoid X-ray irradiation of the head and neck during childhood, maintain a positive mood, and avoid staying up late. However, there are currently no effective preventive measures. Early detection and treatment of the disease are the best ways to prevent its progression.

What Should Thyroid Adenoma Patients Pay Attention to Prevent Recurrence?

To prevent the recurrence of thyroid adenoma, it is best to reduce the intake of seafood and avoid iodine-rich foods such as kelp, dried shrimp, and seaweed. Fatigue should be avoided in daily life, and a relaxed mood should be maintained. Additionally, taking Levothyroxine as prescribed by a doctor can help prevent recurrence.