Riedel's invasive fibrous thyroiditis is a rare disorder of unknown origin with 
progressive extension and invasion of adjacent structures. Clinically it is 
impossible to distinguish between Riedel's/thyroiditis and other diseases as 
undifferentiated carcinoma, Hashimoto's disease etc... The patients often have 
dyspnea, dysphagia, paralysis of the vocal cord; fine needle puncture-aspiration 
and biopsy themselves may be insufficient, Surgical treatment depends on the 
stage of the disease, when both lobes are involved generous wedge resection of 
the isthmus may be the treatment of choice to relieve tracheal compression; in 
earlier stages radical operation are considered. Corticosteroid treatment in 
Riedel's thyroiditis, as multifocal disease has been successfully used. Other 
drugs with antifibrosing actions have also utilised in small groups of patients 
with encouraging results.