Which of the following is true about Riedel's thyroiditis -
Ans. is 'd' i.e. All the above Riedel thyroiditiso A rare disorder characterized by extensive fibrosis involving the thyroid and contiguous neck structures,o The presence of a hard and fixed thyroid mass clinically simulates a thyroid carcinoma.o It may be associated with fibrosis in other sites in the body, such as the retroperitoneum, and appears to be another manifestation of a systemic autoimmune IgG4-related disease, which is associated with fibrosis and tissue infiltration by plasma cells producing IgG4.
Fibrosis involves the thyroid and surrounding neck structures
Patient presents with hard fixed thyroid mass
It may be associated with retroperitoneal fibrosis
All the above