{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,29]],"date-time":"2026-07-29T10:02:16Z","timestamp":1785319336500,"version":"3.55.0"},"reference-count":16,"publisher":"The Endocrine Society","issue":"9","license":[{"start":{"date-parts":[[2026,7,29]],"date-time":"2026-07-29T00:00:00Z","timestamp":1785283200000},"content-version":"vor","delay-in-days":2,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,7,27]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Primary hyperparathyroidism occurs in up to 95% of patients with multiple endocrine neoplasia type 1 (MEN1). However, only a few cases of parathyroid carcinoma have been reported, and only one case of intrathyroidal parathyroid carcinoma. We describe the case of a 41-year-old male with a history of MEN1 and primary hyperparathyroidism who developed hypercalcemia to 13.1\u2005mg\/dL (SI: 3.3\u2005mmol\/L) (reference range [RR], 8.6-10.3\u2005mg\/dL [SI: 2.2-2.6\u2005mmol\/L]) with parathyroid hormone (PTH) 454\u2005pg\/mL (SI: 48.1\u2005pmol\/L) (RR, 15-65\u2005pg\/mL [SI: 1.6-6.9\u2005pmol\/L]). Neck ultrasonography showed a highly suspicious intrathyroidal 3.6\u2005cm nodule. The patient had a lobectomy, and final pathology showed a 3.1 \u00d7 1.6 \u00d7 1.2\u2005cm parathyroid carcinoma. After the surgery, calcium dropped to 6.0\u2005mg\/dL (SI: 1.5\u2005mmol\/L) with PTH of 11\u2005pg\/mL (SI: 1.2\u2005pmol\/L) requiring oral calcium supplements, calcitriol, and hydrochlorothiazide. Laboratory tests at 12 months on these medications showed calcium of 9.3\u2005mg\/dL (SI: 2.3\u2005mmol\/L) and PTH 21\u2005pg\/mL (SI: 2.2\u2005pmol\/L) indicating recovery of parathyroid function without recurrence, and calcitriol was discontinued. This case illustrates that a high index of suspicion for malignancy should be maintained for intrathyroidal parathyroid adenoma in the setting of severe hypercalcemia, especially in MEN1.<\/jats:p>","DOI":"10.1210\/jcemcr\/luag211","type":"journal-article","created":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T11:23:22Z","timestamp":1783941802000},"source":"Crossref","is-referenced-by-count":0,"title":["Intrathyroidal parathyroid carcinoma in a patient with multiple endocrine neoplasia type 1"],"prefix":"10.1210","volume":"4","author":[{"ORCID":"https:\/\/orcid.org\/0009-0001-3018-3261","authenticated-orcid":false,"given":"Arita","family":"Thatte","sequence":"first","affiliation":[{"name":"Division of Endocrinology, Gerontology, and Metabolism, Department of Medicine, Stanford University School of Medicine , Stanford, CA 94305 ,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-3192-6989","authenticated-orcid":false,"given":"Marina","family":"Basina","sequence":"additional","affiliation":[{"name":"Division of Endocrinology, Gerontology, and Metabolism, Department of Medicine, Stanford University School of Medicine , Stanford, CA 94305 ,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4680-1965","authenticated-orcid":false,"given":"Kaniksha","family":"Desai","sequence":"additional","affiliation":[{"name":"Division of Endocrinology, Gerontology, and Metabolism, Department of Medicine, Stanford University School of Medicine , Stanford, CA 94305 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