title: Hashimoto's thyroiditis presenting as a retropharyngeal mass.
mesh_terms: D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D008875:Middle Aged; D010610:Pharyngeal Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D011859:Radiography; D013967:Thyroiditis, Autoimmune / Q000000981:diagnostic imaging* / Q000473:pathology