title: Spindle epithelial tumor with thymus-like differentiation (SETTLE): youngest reported patient.
abstract: Spindle epithelial tumor with thymus-like differentiation (SETTLE) is a very rare thyroid tumor. It is one of a family of tumors arising either from ectopic thymus or remnants of branchial pouches that retain the potential to differentiate along the thymic line. Herein is reported a case of SETTLE in a 2-year-old girl. The patient underwent right thyroid lobectomy for a tumor of the right thyroid lobe. The resected specimen of this tumor revealed a whitish and solid mass. On microscopy, the tumor exhibited an area of spindle cells, glandular epithelium, and mucinous cystic lesions. The following findings were obtained on immunohistochemistry: the spindle cell area was diffusely positive for cytokeratin AE1/3 and vimentin, and partially positive for alpha-smooth muscle-specific actin. The glandular structures consisted of columnar cells and the cystic area was also positive for cytokeratin AE1/3. All three components of the tumor were negative for thyroglobulin, thyroid transcription factor-1, S-100 protein, carcinoembryonic antigen, somatostatin, synaptophysin, and chromogranin A. On the basis of the aforementioned findings, SETTLE was diagnosed. The patient remains disease free to date, 2 years after surgery with no additional treatment. To the best of the authors' knowledge the present SETTLE patient is the youngest yet reported.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Faculty of Medicine, Saga University, Saga City, Nabeshima, Japan. satos3@cc.saga-u.ac.jp
authors.forename: Shintaro
authors.initials: S
authors.lastname: Satoh
authors.forename: Shuji
authors.initials: S
authors.lastname: Toda
authors.forename: Keita
authors.initials: K
authors.lastname: Narikawa
authors.forename: Keiko
authors.initials: K
authors.lastname: Watanabe
authors.forename: Kuniyoshi
authors.initials: K
authors.lastname: Tsuda
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Kuratomi
authors.forename: Hajime
authors.initials: H
authors.lastname: Sugihara
authors.forename: Akira
authors.initials: A
authors.lastname: Inokuchi
mesh_terms: D002277:Carcinoma / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D013950:Thymus Gland / Q000473:pathology*; D013964:Thyroid Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery