**Question:** TRUE/FALSE about solitary thyroid nodule are: 1. Mostly benign in young patients; 2. Hot nodule indicates malignancy; 3. Diffuse hyperplasia of thyroid; 4. Common in females; 5. Thyroidectomy done.

**Core Concept:** Solitary thyroid nodules are localized swellings within the thyroid gland, which may be benign or malignant. Thyroid nodules are relatively common, affecting up to 5% of the general population. They are often incidentally detected during imaging studies or physical examination. Understanding their characteristics and management is crucial for healthcare professionals, particularly in making accurate differential diagnoses and planning appropriate treatments.

**Why the Correct Answer is Right:**

1. Correct Answer: B. Mostly benign in young patients
- Solitary thyroid nodules can be either benign or malignant, with the majority being benign.
- The age distribution of solitary thyroid nodules does not significantly differ between young patients and older individuals; thus, stating that they are "mostly benign in young patients" is incorrect.

2. Correct Answer: A. Hot nodule indicates malignancy
- A hot nodule on a thyroid scan refers to a nodule with increased uptake of radioactive iodine, which is used to differentiate benign from malignant thyroid nodules.
- A hot nodule does not necessarily indicate malignancy, as it can also be seen in benign conditions, such as Graves' disease or focal thyroiditis.

3. Incorrect Answer: D. Diffuse hyperplasia of thyroid
- Diffuse hyperplasia refers to the enlargement of the entire thyroid gland due to hyperfunctioning thyroid cells.
- Solitary thyroid nodules are not associated with diffuse hyperplasia; thus, stating that "Diffuse hyperplasia of thyroid" is incorrect.

4. Correct Answer: C. Common in females
- Solitary thyroid nodules are more prevalent in females, with a female-to-male ratio of 3:1.
- This gender distribution supports the statement that "Common in females" is correct.

5. Correct Answer: D. Thyroidectomy is done
- Solitary thyroid nodules may be managed conservatively or surgically, depending on their characteristics, size, and growth rate.
- Thyroidectomy (surgical removal of the affected thyroid gland) is one option for managing solitary thyroid nodules, particularly when they cause symptoms or are associated with thyroid cancer.

**Why Each Wrong Answer is Incorrect:**

1. Incorrect Answer: A. Not associated with Hashimoto's thyroiditis
- Hashimoto's thyroiditis is an autoimmune disease causing hypothyroidism, not associated with solitary thyroid nodules.

2. Incorrect Answer: E. Causes rapid enlargement
- Solitary thyroid nodules can cause rapid enlargement, but this statement does not specifically address the characteristics of solitary thyroid nodules.

**Clinical Pearls:**

In clinical practice, it is