Struma lymphomatosa (Hashimoto) is a rare type of abnormality of the thyroid gland, first described by Hashimoto in 1912.1 Because of the infrequency of its occurrence, this type of goiter has been discussed almost exclusively by pathologists who, following Hashimoto's work, occasionally have noted in certain cases the curious histology which he described. By clinicians this lymphoid infiltration of the thyroid is generally considered as a type of chronic thyroiditis, usually Riedel's struma, which it closely resembles in many respects.2 Since, however, pathologists3 occasionally report this rare condition, it is of importance that the clinical features of struma lymphomatosa be reviewed and the results of treatment noted. The fundamental picture in struma lymphomatosa is that of a degenerative change in the thyroid gland, unaccompanied by evidence of acute inflammatory process. Microscopically one sees a diffuse lymphoid infiltration between the follicles, with the frequent formation of secondary nodules.