As I1 pointed out in a recent article on the subject, I feel that Riedel's struma is the result of a previous perithyroiditis which causes a partial constriction of the vessels entering the thyroid gland. Another case of Riedel's struma, in which I lately operated, has served to strengthen my belief that such is the etiology of this condition and has, in addition, focused my attention on perithyroiditis as a distinct entity.
My own observations on a series of cases, including the one here reported in detail, have convinced me of the etiologic relationship between perithyroiditis and woody thyroiditis. I believe that, as a result of the perithyroiditis, the fibrous growth characteristic of the disease begins outside rather than within the thyroid gland. Histologic evidence indicates that, as a sequel to perithyroiditis and its complications, there results partial occlusion of the blood vessels entering the gland with subsequent formation
DeCOURCY JL. PERITHYROIDITISA DISTINCT ENTITY. JAMA. 1943;123(7):397–399. doi:10.1001/jama.1943.02840420009004