{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T01:26:43Z","timestamp":1783906003300,"version":"3.55.0"},"reference-count":9,"publisher":"The Endocrine Society","issue":"8","license":[{"start":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T00:00:00Z","timestamp":1783900800000},"content-version":"vor","delay-in-days":11,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,7,2]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Normocalcemic primary hyperparathyroidism (PHPT) is increasingly recognized as an early or indeterminate disease form. Although estrogen is believed to modulate calcium homeostasis, its role in progression to overt PHPT remains incompletely understood. A parathyroid adenoma was suspected in a 33-year-old woman despite normal calcium and parathyroid hormone (PTH) levels. At 37 years of age, approximately 6 months after starting dienogest 0.5\u2005mg twice daily for menorrhagia, she developed prolonged amenorrhea and improved anemia. The PTH level subsequently increased from 38 to 57\u2005pg\/mL (SI: 4.0-6.0\u2005pmol\/L) (reference range 10-65\u2005pg\/mL [SI: 1.1-6.9\u2005pmol\/L]) with mild hypercalcemia (corrected calcium, 10.3\u2005mg\/dL [SI: 2.58\u2005mmol\/L]) (reference range, 8.8-10.1\u2005mg\/dL [SI: 2.20-2.53\u2005mmol\/L]). Despite the prolonged amenorrhea, her estradiol levels were not suppressed. The dienogest was discontinued preoperatively and menstruation resumed; however, the hypercalcemia and elevated PTH persisted. Imaging revealed the parathyroid adenoma. Upon its resection, the PTH level promptly normalized. Altered estrogen dynamics rather than an absolute estrogen deficiency may have contributed to the transition to overt PHPT noted herein. Manifested hypercalcemia is not readily reversible, suggesting a shift to a self-sustaining state. This case raises the possibility that altered hormonal dynamics may contribute to the manifestation of PHPT.<\/jats:p>","DOI":"10.1210\/jcemcr\/luag188","type":"journal-article","created":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T01:03:03Z","timestamp":1783904583000},"source":"Crossref","is-referenced-by-count":0,"title":["Primary hyperparathyroidism unmasking after dienogest-altered estrogen dynamics: implications for calcium homeostasis"],"prefix":"10.1210","volume":"4","author":[{"ORCID":"https:\/\/orcid.org\/0009-0001-0805-8886","authenticated-orcid":false,"given":"Hiroyuki","family":"Yamashita","sequence":"first","affiliation":[{"name":"Department of Surgery, Yamashita Thyroid Hospital , Fukuoka City, Fukuoka 812-0034 ,","place":["Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9802-3697","authenticated-orcid":false,"given":"Daisuke","family":"Tatsushima","sequence":"additional","affiliation":[{"name":"Department of Surgery, Yamashita Thyroid Hospital , Fukuoka City, Fukuoka 812-0034 ,","place":["Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1424-620X","authenticated-orcid":false,"given":"Hisakazu","family":"Shindo","sequence":"additional","affiliation":[{"name":"Department of Surgery, Yamashita Thyroid Hospital , Fukuoka City, Fukuoka 812-0034 ,","place":["Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-4297-134X","authenticated-orcid":false,"given":"Yusuke","family":"Mori","sequence":"additional","affiliation":[{"name":"Department of Surgery, Yamashita Thyroid Hospital , Fukuoka City, Fukuoka 812-0034 ,","place":["Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-2844-1823","authenticated-orcid":false,"given":"Kento","family":"Katsuyama","sequence":"additional","affiliation":[{"name":"Department of Surgery, Yamashita Thyroid Hospital , Fukuoka City, Fukuoka 812-0034 ,","place":["Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0761-6209","authenticated-orcid":false,"given":"Shinya","family":"Sato","sequence":"additional","affiliation":[{"name":"Department of Surgery, Yamashita Thyroid Hospital , Fukuoka City, Fukuoka 812-0034 ,","place":["Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"80","published-online":{"date-parts":[[2026,7,13]]},"reference":[{"issue":"1","key":"2026071221004370600_luag188-B1","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1016\/j.jocd.2012.12.001","article-title":"Normocalcemic primary hyperparathyroidism","volume":"16","author":"Cusano","year":"2013","journal-title":"J Clin Densitom"},{"issue":"11","key":"2026071221004370600_luag188-B2","doi-asserted-by":"crossref","first-page":"2315","DOI":"10.1002\/jbmr.4665","article-title":"Epidemiology, pathophysiology, and genetics of primary hyperparathyroidism","volume":"37","author":"Minisola","year":"2022","journal-title":"J Bone Miner Res"},{"issue":"11","key":"2026071221004370600_luag188-B3","doi-asserted-by":"crossref","first-page":"2293","DOI":"10.1002\/jbmr.4677","article-title":"Evaluation and management of primary hyperparathyroidism: summary statement and guidelines from the fifth international workshop","volume":"37","author":"Bilezikian","year":"2022","journal-title":"J Bone Miner Res"},{"issue":"4","key":"2026071221004370600_luag188-B4","doi-asserted-by":"crossref","first-page":"831","DOI":"10.1210\/jcem-68-4-831","article-title":"Estrogen replacement decreases the set point of parathyroid hormone stimulation by calcium in normal postmenopausal women","volume":"68","author":"Boucher","year":"1989","journal-title":"J Clin Endocrinol Metab"},{"issue":"5","key":"2026071221004370600_luag188-B5","doi-asserted-by":"crossref","first-page":"337","DOI":"10.7326\/0003-4819-118-5-199303010-00003","article-title":"Estrogen protection against bone resorbing effects of parathyroid hormone infusion. 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