| struma ovarii | A rare teratoid tumour of the ovary composed almost entirely of thyroid tissue, with large follicles containing abundant colloid. Occasionally there are symptoms of hyperthyroidism. 5-10% of struma ovarii become malignant, the only absolute criterion for which is the presence of metastasis. (12 Dec 1998) |
|---|---|
| ligneous struma | A rare fibrous induration of the thyroid gland, with adhesion to adjacent structures, which may cause tracheal compression. Synonym: chronic fibrous thyroiditis, ligneous struma, ligneous thyroiditis, Riedel's disease, Riedel's struma. (05 Mar 2000) |