Nodules are small, rounded lumps that can form in various parts of the body, including the skin, lungs, and thyroid gland. They can vary in size and may be solid or filled with fluid. Nodules can be benign, meaning they are not harmful, or malignant, indicating the presence of cancer. In the case of the thyroid gland, nodules are common and often discovered during routine medical exams. Most thyroid nodules do not cause symptoms, but some may affect hormone levels or lead to discomfort. Medical evaluation is important to determine their nature and whether treatment is needed.