Is a solid nodule on the isthmus serious?

It depends on the nature of the nodule. Benign nodules, such as thyroid nodules, are usually not serious and do not require treatment. However, malignant nodules, such as thyroid cancer, can be serious and require prompt treatment. If you have a solid nodule on the isthmus, it is important to see a doctor to determine its nature and receive appropriate treatment if necessary.