Table 1 Benign and Malignant causes of thyroid nodules

Benign

 Colloid nodule

 Hashimoto thyroiditis

 Simple or hemorrhagic cyst

 Follicular adenoma

 Subacute thyroiditis

Malignant

 Primary

  Follicular cell-derived carcinoma:

   PTC, follicular thyroid carcinoma, anaplastic thyroid carcinoma

  C-cell–derived carcinoma:

   MTC

  Thyroid lymphoma

 Secondary

  Metastatic carcinoma (3 most common primaries are renal, lung & head-neck)