Martinez-Montoro, Jose IgnacioGomez-Perez, Ana MariaGallego, ElenaGarcia-Aleman, JorgeSebastian-Ochoa, ArantzazuDamas-Fuentes, MiguelMancha-Doblas, IsabelTinahones, Francisco J2023-05-032023-05-032022-04-20Martínez-Montoro JI, Gómez-Pérez AM, Gallego E, García-Alemán J, Sebastián-Ochoa A, Damas-Fuentes M, et al. "Triple-negative" non-secretory medullary thyroid cancer: uncommon pathological findings in a rare disease. Arch Med Sci. 2022 Apr 20;18(3):825-828.1734-1922http://hdl.handle.net/10668/21653Medullary thyroid cancer (MTC) is a neuroendocrine tumor that arises from the calcitonin (CT)-producing thyroid parafollicular C cells, accounting for 3–4% of all thyroid cancers [1, 2]. CT constitutes the most specific and sensitive serum biomarker of MTC and correlates with tumor size [3], whereas different markers markers, such as carcinoembryonic antigen (CEA) and chromogranin A (CgA), are specific but often co-secreted by the tumor [2, 3]. Compared with other thyroid malignancies, MTC exhibits distinctive histopathological features, and the most important immunohistochemical markers are CT and CEA; in fact, in the absence of CT expression, the diagnosis of MTC should be questioned [4]. Also, amyloid material is often present at the histological examination [4]. Calcitonin-negative medullary thyroid cancer (CNMTC), determined by normal serum levels of CT, is a very rare presentation of MTC and only a few cases have been described in the literature [5]. Moreover, CNMTC is often positive for CT immunostaining [6]. In the current case, we report a CNMTC with negative CT, CEA and amyloid substance at the histopathological examinationenAttribution-NonCommercial-ShareAlike 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-sa/4.0/Medullary thyroid cancerMedullary thyroid cancerNeuroendocrine tumorTumor markersImmunohistochemistryCarcinoembryonic antigenChromogranin AThyroid neoplasmsCarcinoma, medullaryCalcitoninCarcinoembryonic antigenChromograninsAmyloidImmunohistochemistryBiomarkers, tumorNeuroendocrine tumorsresearch article35591839open accessNeoplasias tiroideasCarcinoma medularCalcitoninaAntígeno carcinoembrionarioCromograninasAmiloideInmunohistoquímicaBiomarcadores tumoralesTumores neuroendocrinos10.5114/aoms/147431PMC9103519https://www.archivesofmedicalscience.com/pdf-147431-75527?filename=_Triple_negative_.pdfhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC9103519/pdf