{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T10:08:31Z","timestamp":1780654111802,"version":"3.54.1"},"reference-count":44,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T00:00:00Z","timestamp":1780617600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background: Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome caused by fibroblast growth factor 23 (FGF-23)-secreting tumors, typically of mesenchymal origin, leading to renal phosphate wasting and severe bone demineralization and fragility fractures. Diagnosing TIO remains a significant clinical challenge, particularly when coexisting mineral metabolism disorders, such as hypercalcemic hyperparathyroidism, are masking its clinical presentation. Case Presentation: A 74-year-old woman with fragility fractures, generalized bone pain, and nephrolithiasis was initially diagnosed with primary hyperparathyroidism due to concomitant hypercalcemia, hypophosphatemia, and elevated parathyroid hormone (PTH). Despite a successful parathyroidectomy, which normalized calcium levels, severe hypophosphatemia persisted due to renal phosphate wasting. High FGF-23 levels and subsequent functional imaging indicating a somatostatin receptor-positive lesion in the left popliteal fossa led to the diagnosis of TIO. Surgical resection immediately normalized FGF-23 levels, leading to a slower rise in phosphorus during follow-up. Histopathology revealed a tophaceous-like giant cell granulomatous reaction, recalling the earlier report by Prader. Conclusions: This case highlights that parathyroid disorders can coexist with TIO, and they may delay its diagnosis. In this circumstance, a high index of clinical suspicion is represented by the persistence of hypophosphatemia post-parathyroidectomy.<\/jats:p>","DOI":"10.3390\/jcm15114368","type":"journal-article","created":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T08:43:04Z","timestamp":1780648984000},"page":"4368","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A Case of Tumor-Induced Osteomalacia Masked by Parathyroid Carcinoma"],"prefix":"10.3390","volume":"15","author":[{"given":"Giulia","family":"Manfredi","sequence":"first","affiliation":[{"name":"Department of Medical, Surgical and Health Sciences, University of Trieste, Cattinara University Hospital, Strada di Fiume 447, 34149 Trieste, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anna","family":"Turisani","sequence":"additional","affiliation":[{"name":"Department of Medical, Surgical and Health Sciences, University of Trieste, Cattinara University Hospital, Strada di Fiume 447, 34149 Trieste, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-4451-365X","authenticated-orcid":false,"given":"Alberto","family":"Piasentier","sequence":"additional","affiliation":[{"name":"Department of Biomedical Sciences, Humanitas Research University, Via Rita Levi Montalcini 4, 20072 Pieve Emanuele (MI), Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5872-3346","authenticated-orcid":false,"given":"Chiara","family":"Dobrinja","sequence":"additional","affiliation":[{"name":"General Surgery Unit, Azienda Sanitaria Universitaria Giuliano Isontina (ASUGI), Cattinara University Hospital, Strada di Fiume 447, 34149 Trieste, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mattia","family":"Mario","sequence":"additional","affiliation":[{"name":"Department of Medical, Surgical and Health Sciences, University of Trieste, Cattinara University Hospital, Strada di Fiume 447, 34149 Trieste, Italy"},{"name":"Pathology Unit, Azienda Sanitaria Universitaria Giuliano Isontina (ASUGI), Cattinara University Hospital, Strada di Fiume 447, 34149 Trieste, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chiara","family":"Ratti","sequence":"additional","affiliation":[{"name":"Orthopaedics and Traumatology Unit, Azienda Sanitaria Universitaria Giuliano Isontina (ASUGI), Cattinara University Hospital, Strada di Fiume 447, 34149 Trieste, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Luigi","family":"Murena","sequence":"additional","affiliation":[{"name":"Department of Medical, Surgical and Health Sciences, University of Trieste, Cattinara University Hospital, Strada di Fiume 447, 34149 Trieste, Italy"},{"name":"Orthopaedics and Traumatology Unit, Azienda Sanitaria Universitaria Giuliano Isontina (ASUGI), Cattinara University Hospital, Strada di Fiume 447, 34149 Trieste, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bruno","family":"Fabris","sequence":"additional","affiliation":[{"name":"Department of Medical, Surgical and Health Sciences, University of Trieste, Cattinara University Hospital, Strada di Fiume 447, 34149 Trieste, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Veronica","family":"Calabro\u2019","sequence":"additional","affiliation":[{"name":"Endocrinology Unit, UCO Medicina Clinica, ASUGI, Cattinara University Hospital, Strada di Fiume 447, 34149 Trieste, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7429-3075","authenticated-orcid":false,"given":"Stella","family":"Bernardi","sequence":"additional","affiliation":[{"name":"Department of Medical, Surgical and Health Sciences, University of Trieste, Cattinara University Hospital, Strada di Fiume 447, 34149 Trieste, Italy"},{"name":"Endocrinology Unit, UCO Medicina Clinica, ASUGI, Cattinara University Hospital, Strada di Fiume 447, 34149 Trieste, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"323","DOI":"10.1210\/endrev\/bnac026","article-title":"Tumor-induced Osteomalacia: A Comprehensive Review","volume":"44","author":"Minisola","year":"2023","journal-title":"Endocr. 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