{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,21]],"date-time":"2026-07-21T08:15:01Z","timestamp":1784621701054,"version":"3.55.0"},"reference-count":18,"publisher":"The Endocrine Society","issue":"10","license":[{"start":{"date-parts":[[2025,9,19]],"date-time":"2025-09-19T00:00:00Z","timestamp":1758240000000},"content-version":"vor","delay-in-days":31,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2025,8,19]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:p>A 33-year-old female individual had a history of a lymph node excision positive for metastatic papillary thyroid carcinoma (PTC) in 2016. She was treated with a total thyroidectomy and central neck dissection showing 0.2-cm micro-PTC without paratracheal lymph node involvement, followed by adjuvant radioactive iodine treatment with 104 mCi of iodine-131. After 9 years without evidence of disease, she presented with a mildly tender, firm, left neck level II mass rapidly enlarging over 3 weeks. Neck ultrasound revealed a 3.5\u2005cm irregular hypoechoic mass with internal vascularity and punctate echogenic foci. A fine needle biopsy showed inflammatory and mature squamous cells with elevated thyroglobulin but no definitive evidence of malignancy. The patient was scheduled for urgent neck dissection; however, just a left lymph node excision was performed as intraoperative frozen pathology showed no cancer. Surgical histopathology showed branchial cleft cyst tissue. The most concerning diagnosis for a rapidly enlarging neck mass in an adult with a history of metastatic PTC is anaplastic thyroid carcinoma. However, other diagnoses such as branchial cleft anomalies, lymphoma, or non-thyroid metastatic malignancies should be considered. Intraoperative frozen section pathology is crucial to direct surgical management of an unknown neck mass concerning for anaplastic thyroid cancer.<\/jats:p>","DOI":"10.1210\/jcemcr\/luaf201","type":"journal-article","created":{"date-parts":[[2025,8,27]],"date-time":"2025-08-27T11:42:12Z","timestamp":1756294932000},"source":"Crossref","is-referenced-by-count":1,"title":["A Misleading Neck Mass: Branchial Cleft Cyst Mimicking Anaplastic Thyroid Carcinoma"],"prefix":"10.1210","volume":"3","author":[{"ORCID":"https:\/\/orcid.org\/0009-0004-8117-5714","authenticated-orcid":false,"given":"Taylor L","family":"Jamil","sequence":"first","affiliation":[{"name":"Department of Otolaryngology, University of Colorado School of Medicine , Aurora, CO 80045 ,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ryan","family":"Thomas","sequence":"additional","affiliation":[{"name":"Department of Pathology, University of Colorado School of Medicine , Aurora, CO 80045 ,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1336-7149","authenticated-orcid":false,"given":"Christie G","family":"Turin","sequence":"additional","affiliation":[{"name":"Division of Endocrinology, Diabetes, and Metabolism, University of Colorado School of Medicine , Aurora, CO 80045 ,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0747-3161","authenticated-orcid":false,"given":"Brian P","family":"Cervenka","sequence":"additional","affiliation":[{"name":"Department of Otolaryngology, University of Colorado School of Medicine , Aurora, CO 80045 ,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8574-1972","authenticated-orcid":false,"given":"Nikita","family":"Pozdeyev","sequence":"additional","affiliation":[{"name":"Division of Endocrinology, Diabetes, and Metabolism, University of Colorado School of Medicine , Aurora, CO 80045 ,","place":["USA"]},{"name":"Department of Biomedical Informatics, University of Colorado School of Medicine , Aurora, CO 80045 ,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"80","published-online":{"date-parts":[[2025,9,19]]},"reference":[{"issue":"12","key":"2025091922222443900_luaf201-B1","doi-asserted-by":"crossref","first-page":"570","DOI":"10.5306\/wjco.v14.i12.570","article-title":"Update on current diagnosis and management of anaplastic thyroid carcinoma","volume":"14","author":"Pavlidis","year":"2023","journal-title":"World J Clin Oncol"},{"key":"2025091922222443900_luaf201-B2","doi-asserted-by":"crossref","first-page":"790834","DOI":"10.1155\/2014\/790834","article-title":"Update on anaplastic thyroid carcinoma: morphological, molecular, and genetic features of the most aggressive thyroid cancer","volume":"2014","author":"Ragazzi","year":"2014","journal-title":"Int J 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