Spindle epithelial tumor with thymus‐like differentiation (SETTLE): Youngest reported patient

• Published in: Pathology international Vol. 56; no. 9; pp. 563 - 567
• Main Authors: Satoh, Shintaro, Toda, Shuji, Narikawa, Keita, Watanabe, Keiko, Tsuda, Kuniyoshi, Kuratomi, Yuichiro, Sugihara, Hajime, Inokuchi, Akira
• Format: Journal Article
• Language: English
• Published: Melbourne, Australia Blackwell Publishing Asia 01.09.2006
• Subjects: Carcinoma - metabolism; Carcinoma - pathology; Carcinoma - surgery; Child, Preschool; Female; Humans; Immunohistochemistry; spindle epithelial tumor with thymus‐like differentiation; Thymus Gland - pathology; thyroid gland; Thyroid Neoplasms - metabolism; Thyroid Neoplasms - pathology; Thyroid Neoplasms - surgery; thyroid tumor in children
• ISSN: 1320-5463; 1440-1827
• DOI: 10.1111/j.1440-1827.2006.02007.x

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 α‐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.