struma ovarii obsolete benign struma ovarii true disease_ontology DOID:5209 An ovarian benign neoplasm struma ovarii that is not cancerous and that is composed either exclusively or predominantly of thyroid tissue. Obsoleted in conjunction with obsoletion of corresponding cross-references (version): NCI:C40012 (29.08d), UMLS_CUI:C1511104 (2023AA). 'struma ovarii' is considered benign making this term redundant.