{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,4]],"date-time":"2025-10-04T07:56:11Z","timestamp":1759564571448,"version":"3.44.0"},"reference-count":11,"publisher":"BMJ","issue":"8","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2020,7,19]]},"published-print":{"date-parts":[[2020,8]]},"abstract":"<jats:p>Hypercalcaemia in malignancy is most commonly caused by paraneoplastic secretion of parathyroid hormone-related protein or osteolytic metastases. Very rarely (&lt;1% of cases), the mechanism behind increased serum calcium is increased production of calcitriol (1,25-dihydroxyvitamin D) and even rarer is the occurrence of this phenomenon in solid malignancies, with few such instances reported in the literature. We present a case of a neuroendocrine malignancy originating in the oesophagus associated with calcitriol-induced hypercalcaemia, a phenomenon that has not been previously described. We review the pathophysiology of calcitriol-induced hypercalcaemia and previously reported cases of solid tumours with this presentation.<\/jats:p>","DOI":"10.1136\/bcr-2020-235209","type":"journal-article","created":{"date-parts":[[2020,8,26]],"date-time":"2020-08-26T01:35:15Z","timestamp":1598405715000},"page":"e235209","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":3,"title":["Unusual behaviour of an unusual tumour: calcitriol-induced hypercalcaemia in metastatic oesophageal neuroendocrine carcinoma"],"prefix":"10.1136","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3097-8985","authenticated-orcid":false,"given":"Filip","family":"Ionescu","sequence":"first","affiliation":[{"name":"Department of Internal Medicine, William Beaumont Hospital, Royal Oak, Michigan, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ioana","family":"Petrescu","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, William Beaumont Hospital, Royal Oak, Michigan, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Maria","family":"Marin","sequence":"additional","affiliation":[{"name":"Department of Nephrology, William Beaumont Hospital, Royal Oak, Michigan, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","published-online":{"date-parts":[[2020,8,25]]},"reference":[{"key":"2025082711271327000_13.8.e235209.1","doi-asserted-by":"crossref","first-page":"373","DOI":"10.1056\/NEJMcp042806","article-title":"Hypercalcemia associated with cancer","volume":"352","author":"Stewart","year":"2005","journal-title":"N Engl J Med Overseas Ed"},{"key":"2025082711271327000_13.8.e235209.2","doi-asserted-by":"publisher","DOI":"10.1001\/archinte.1987.00370120148027"},{"key":"2025082711271327000_13.8.e235209.3","article-title":"Hypercalcemia due to paraneoplastic production of 1,25- dihydroxyvitamin D in a young female with dysgerminoma","volume":"11","author":"Iqbal","year":"2019","journal-title":"Cureus"},{"key":"2025082711271327000_13.8.e235209.4","doi-asserted-by":"publisher","DOI":"10.1007\/s002470050327"},{"key":"2025082711271327000_13.8.e235209.5","doi-asserted-by":"publisher","DOI":"10.1080\/08880010701774033"},{"key":"2025082711271327000_13.8.e235209.6","first-page":"E84","article-title":"Hypercalcemia from metastatic pancreatic neuroendocrine tumor secreting 1,25-dihydroxyvitamin D","volume":"5","author":"Zhu","year":"2014","journal-title":"J Gastrointest Oncol"},{"key":"2025082711271327000_13.8.e235209.7","doi-asserted-by":"crossref","DOI":"10.1136\/bcr-2017-220819","article-title":"Twist on a classic: vitamin D and hypercalcaemia of malignancy","volume":"2017","author":"Osorio","year":"2017","journal-title":"BMJ Case Rep"},{"key":"2025082711271327000_13.8.e235209.8","doi-asserted-by":"crossref","first-page":"234","DOI":"10.4158\/EP.15.3.234","article-title":"Hypercalcemia of malignancy with simultaneous elevation in serum parathyroid hormone--related peptide and 1,25-dihydroxyvitamin D in a patient with metastatic renal cell carcinoma","volume":"15","author":"Shivnani","year":"2009","journal-title":"Endocr Pract"},{"key":"2025082711271327000_13.8.e235209.9","doi-asserted-by":"publisher","DOI":"10.1210\/jc.2013-2016"},{"key":"2025082711271327000_13.8.e235209.10","doi-asserted-by":"crossref","first-page":"92","DOI":"10.1016\/j.critrevonc.2019.02.012","article-title":"A rare rarity: neuroendocrine tumor of the esophagus","volume":"137","author":"Giannetta","year":"2019","journal-title":"Crit Rev Oncol Hematol"},{"key":"2025082711271327000_13.8.e235209.11","doi-asserted-by":"publisher","DOI":"10.7326\/0003-4819-111-5-437"}],"container-title":["BMJ Case Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bcr-2020-235209","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,8,27]],"date-time":"2025-08-27T18:27:21Z","timestamp":1756319241000},"score":1,"resource":{"primary":{"URL":"https:\/\/casereports.bmj.com\/lookup\/doi\/10.1136\/bcr-2020-235209"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,8]]},"references-count":11,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2020,8,25]]},"published-print":{"date-parts":[[2020,8]]}},"alternative-id":["10.1136\/bcr-2020-235209"],"URL":"https:\/\/doi.org\/10.1136\/bcr-2020-235209","relation":{},"ISSN":["1757-790X"],"issn-type":[{"type":"electronic","value":"1757-790X"}],"subject":[],"published":{"date-parts":[[2020,8]]}}}