You may see the following three non-neoplastic diseases of the thyroid. Apart from lymphocytic thyroiditis they are uncommon, and you may have to do a needle biopsy to distinguish them.
OTHER THYROID PROBLEMS If a goitre is uniform and feels unusually FIRM and VERY WELL-DEFINED but is not particularly tender, consider the possibility of autoimmune lymphocytic thyroiditis (Hashimoto's disease, not uncommon). The patient is aged 20 to 70, and is usually about 50. Women are more commonly affected than men. Spontaneous resolution is usual but slow. Hypothyroidism often develops, and needs replacement therapy with l-thyroxine 100 to 200 micrograms daily. Prednisolone is of doubtful value.
If a patient's thyroid has become uniformly enlarged, MODERATELY TENDER, and PAINFUL over some weeks or months, he may have subacute thyroiditis (de Quervain's disease, uncommon). This is a non-suppurative inflammation, sometimes with hyperthyroidism. The ESR is raised. It is self-limiting, but you can promote its resolution by giving him prednisolone 30 mg daily, until his pain and swelling subside. He has a 10% chance of becoming hypothyroid.
If his thyroid becomes WOODY-HARD, is fixed to the surrounding tissues, and is either normal-sized or a little enlarged, suspect RIELEL'S THYROIDITIS (woody thyroiditis, rare). Distinguish this from malignant tumours.