{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T14:17:53Z","timestamp":1784557073923,"version":"3.55.0"},"reference-count":0,"publisher":"Bioscientifica","license":[{"start":{"date-parts":[[2021,7,1]],"date-time":"2021-07-01T00:00:00Z","timestamp":1625097600000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":["edm.bioscientifica.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2021,7,1]]},"abstract":"\n Summary<\/jats:title>\n Anaplastic thyroid cancer (ATC) is the type of thyroid cancer that has the worst prognosis. It usually presents as a rapidly growing cervical mass that generates compressive symptoms. Its association with thyrotoxicosis is rare. A 76-year-old woman, with no contributory history, presented with a 3-month course of fast-growing cervical tumor, associated with tenderness, cough, and weight loss. Physical examination revealed goiter, localized erythema, and a painful and stone tumor dependent on the right thyroid lobe. Due to the malignant findings of the thyroid ultrasound, the patient underwent a thyroid core needle biopsy, which indicated ATC. Laboratory tests revealed leukocytosis, decreased thyroid-stimulating hormone, elevated free thyroxine (fT4), and increased thyroperoxidase (TPO) antibodies. At the beginning, we considered that the etiology of thyrotoxicosis was secondary to subacute thyroiditis (SAT) after SARS-CoV-2 infection, due to the immunochromatography result and chest tomography findings. The result of markedly elevated TPO antibodies left this etiology more remote. Therefore, we suspected Graves\u2019 disease as an etiology; however, thyroid histopathology and ultrasound did not show compatible findings. Therefore, we suspect that the main etiology of thyrotoxicosis in the patient was the destruction of the thyroid follicles caused by a rapid invasion of malignant cells, which is responsible for the consequent release of preformed thyroid hormone. ATC is a rare endocrine neoplasm with high mortality; it may be associated with thyrotoxicosis, whose etiology can be varied; therefore, differential diagnosis is important for proper management.<\/jats:p>\n <\/jats:sec>\n \n Learning points<\/jats:title>\n \n \n Anaplastic thyroid cancer is the thyroid cancer with the worst prognosis and the highest mortality.<\/jats:p>\n <\/jats:list-item>\n \n The association of anaplastic thyroid cancer with thyrotoxicosis is rare, and a differential diagnosis is necessary to provide adequate treatment.<\/jats:p>\n <\/jats:list-item>\n \n Due to the current pandemic, in patients with thyrotoxicosis, it is important to rule out SARS-CoV-2 as an etiology.<\/jats:p>\n <\/jats:list-item>\n \n Anaplastic thyroid cancer, due to its aggressive behavior and rapid growth, can destroy thyroid follicular cells, generating preformed thyroid hormone release, being responsible for thyrotoxicosis.<\/jats:p>\n <\/jats:list-item>\n <\/jats:list>\n <\/jats:sec>","DOI":"10.1530\/edm-21-0053","type":"journal-article","created":{"date-parts":[[2021,7,1]],"date-time":"2021-07-01T06:21:21Z","timestamp":1625120481000},"update-policy":"https:\/\/doi.org\/10.1530\/crossmarkpolicy-2","source":"Crossref","is-referenced-by-count":0,"title":["New-onset thyrotoxicosis in a patient with anaplastic thyroid carcinoma: a diagnostic challenge"],"prefix":"10.1530","volume":"2021","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9719-1875","authenticated-orcid":true,"given":"Marcio Jos\u00e9","family":"Concepci\u00f3n Zavaleta","sequence":"first","affiliation":[{"name":"1Division of Endocrinology, Hospital Nacional Guillermo Almenara Irigoyen, Lima, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1952-2338","authenticated-orcid":true,"given":"Sofia Pilar","family":"Ildefonso Najarro","sequence":"additional","affiliation":[{"name":"2Division of Endocrinology, Hospital Nacional Guillermo Almenara Irigoyen, Lima, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8766-7083","authenticated-orcid":true,"given":"Esteban Alberto","family":"Plasencia Due\u00f1as","sequence":"additional","affiliation":[{"name":"1Division of Endocrinology, Hospital Nacional Guillermo Almenara Irigoyen, Lima, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5396-7360","authenticated-orcid":true,"given":"Mar\u00eda Alejandra","family":"Quispe Flores","sequence":"additional","affiliation":[{"name":"1Division of Endocrinology, Hospital Nacional Guillermo Almenara Irigoyen, Lima, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7390-3150","authenticated-orcid":true,"given":"Diego Mart\u00edn","family":"Moreno Marreros","sequence":"additional","affiliation":[{"name":"3Facultad de Medicina de la Universidad Nacional de Trujillo, Trujillo, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0462-3101","authenticated-orcid":true,"given":"Luis Alberto","family":"Concepci\u00f3n Urteaga","sequence":"additional","affiliation":[{"name":"4Division of Neumology, Hospital Regional Docente de Trujillo, Trujillo, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3938-5572","authenticated-orcid":true,"given":"Laura Esther","family":"Luna Victorio","sequence":"additional","affiliation":[{"name":"5Division of Endocrinology, Hospital Nacional Guillermo Almenara Irigoyen, Lima, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6468-2106","authenticated-orcid":true,"given":"Freddy Valdivia","family":"Fern\u00e1ndez D\u00e1vila","sequence":"additional","affiliation":[{"name":"5Division of Endocrinology, Hospital Nacional Guillermo Almenara Irigoyen, Lima, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"416","container-title":["Endocrinology, Diabetes & Metabolism Case Reports"],"original-title":[],"link":[{"URL":"https:\/\/edm.bioscientifica.com\/view\/journals\/edm\/2021\/1\/EDM21-0053.xml","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/edm.bioscientifica.com\/downloadpdf\/journals\/edm\/2021\/1\/EDM21-0053.xml","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T13:47:40Z","timestamp":1784555260000},"score":1,"resource":{"primary":{"URL":"http:\/\/journals.bioscientifica.com\/edm\/article\/3470"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,7,1]]},"references-count":0,"URL":"https:\/\/doi.org\/10.1530\/edm-21-0053","relation":{},"ISSN":["2052-0573"],"issn-type":[{"value":"2052-0573","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,7,1]]}}}