{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,4]],"date-time":"2026-08-04T14:20:43Z","timestamp":1785853243691,"version":"3.56.0"},"reference-count":29,"publisher":"The Endocrine Society","issue":"4","license":[{"start":{"date-parts":[[2025,3,19]],"date-time":"2025-03-19T00:00:00Z","timestamp":1742342400000},"content-version":"vor","delay-in-days":2,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["T32DK007058-50"],"award-info":[{"award-number":["T32DK007058-50"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2025,3,17]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:p>Extraosseous giant cell tumor of bone (GCTB) associated with Paget disease of bone (PDB) is rare. We report a patient aged in their 70s with polyostotic PDB involving the skull, spine, and pelvis, previously treated with bisphosphonates, who presented with symptomatic hypercalcemia (calcium 14.8\u2005mg\/dL [3.7\u2005mmol\/L]; reference range [RR], 8.6-10.5\u2005mg\/dL [2.1-2.6\u2005mmol\/L]), kidney injury (creatinine 2.6\u2005mg\/dL [230\u2005\u03bcmol\/L]; RR, 0.4-1.1\u2005mg\/dL [35-97\u2005\u03bcmol\/L]), and a 17.5\u2005cm pelvic mass. Testing showed elevated calcitriol or 1,25-dihydroxyvitamin D (1,25(OH)2D) (57-108\u2005pg\/mL [137-259\u2005pmol\/L]; RR, 18-72\u2005pg\/mL [43-173\u2005pmol\/L]), but normal parathyroid hormone and bone-specific alkaline phosphatase (BSAP), arguing against parathyroid autonomy and active osseous PDB. Histopathology showed osteoclast-like giant cells and stromal mononuclear cells without atypia, necrosis, or mitoses. A one-time dose of denosumab 120\u2005mg resulted in normalized calcium (9.0\u2005mg\/dL [2.2\u2005mmol\/L]) and 1,25(OH)2D (24\u2005pg\/mL [57\u2005pmol\/L]) and reduced tumor size. Denosumab was continued at a dose of 60\u2005mg every 6 months. After 20 months, calcium and 1,25(OH)2D remained normal, with no tumor regrowth, and BSAP stayed low. This is the first report of 1,25(OH)2D-mediated hypercalcemia in extraosseous GCTB. It responded well to denosumab. Long-term management options are discussed in the context of existing literature.<\/jats:p>","DOI":"10.1210\/jcemcr\/luaf031","type":"journal-article","created":{"date-parts":[[2025,3,19]],"date-time":"2025-03-19T08:10:42Z","timestamp":1742371842000},"source":"Crossref","is-referenced-by-count":3,"title":["Treatment of Extraosseous Giant Cell Tumor of Bone and Calcitriol-Mediated Hypercalcemia With Denosumab in Paget Disease"],"prefix":"10.1210","volume":"3","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2426-9157","authenticated-orcid":false,"given":"Oyunbileg","family":"Magvanjav","sequence":"first","affiliation":[{"name":"Section of Endocrinology and Metabolism, Yale University School of Medicine , New Haven, CT 06519 ,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7518-249X","authenticated-orcid":false,"given":"Clemens","family":"Bergwitz","sequence":"additional","affiliation":[{"name":"Section of Endocrinology and Metabolism, Yale University School of Medicine , New Haven, CT 06519 ,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"80","published-online":{"date-parts":[[2025,3,19]]},"reference":[{"issue":"2","key":"2025031908103406000_luaf031-B1","doi-asserted-by":"crossref","first-page":"257","DOI":"10.1002\/jbmr.2349","article-title":"Clinical characteristics and evolution of giant cell tumor occurring in Paget's disease of bone","volume":"30","author":"Rendina","year":"2015","journal-title":"J Bone Miner Res"},{"issue":"4","key":"2025031908103406000_luaf031-B2","doi-asserted-by":"crossref","first-page":"2112","DOI":"10.3390\/curroncol31040157","article-title":"Current concepts in the treatment of giant cell tumor of bone: an update","volume":"31","author":"Tsukamoto","year":"2024","journal-title":"Curr 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