title: Cystic goiter with squamous-cell metaplasia--case report and comment on origin of squamous-cell cyst.
abstract: A 53-year-old woman with a left unilocular cystic goiter of the size of a small orange was reported. Approximately four-tenths of the innter surface was lined with several layered squamous epithelium with few follicles remaining. A gradual metaplastic transition from the follicular epithelium to the flattened cuboidal and to the squamous epithelium was observed. The ultimobranchial body has been understood to be a possible origin of an entirely squamous cell cyst of the thyroid, three of which have been reported. The difference between the ultimo-branchial and metaplastic origins will be discussed, and a new designation-primary (ultimo-branchial) and secondary (metaplastic) squamous-cell cyst will be proposed.
mesh_terms: D000818:Animals; D003560:Cysts / Q000209:etiology / Q000473:pathology*; D004847:Epithelial Cells; D004848:Epithelium / Q000648:ultrastructure; D005260:Female; D006042:Goiter / Q000209:etiology / Q000473:pathology*; D006801:Humans; D008679:Metaplasia; D008875:Middle Aged; D013961:Thyroid Gland / Q000473:pathology; D014460:Ultimobranchial Body / Q000473:pathology