1. Hypercalcemia Owing to Overproduction of 1,25-Dihydroxyvitamin D3 in Fetal Lung Adenocarcinoma: Case Report
- Author
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Tomohito Saito, MD, PhD, Mistuaki Ishida, MD, PhD, Makiko Kusabe, MD, Takahiro Utsumi, MD, Natsumi Maru, MD, Hiroshi Matsui, MD, Yohei Taniguchi, MD, PhD, Takayasu Kurata, MD, PhD, Hiroaki Kurokawa, MD, PhD, Takanobu Imada, MD, PhD, Koji Tsuta, MD, PhD, Hiroyasu Tsukaguchi, MD, PhD, and Tomohiro Murakawa, MD, PhD
- Subjects
Hypercalcemia of malignancy ,Lung cancer ,1,25-Dihydroxyvitamin D3 ,Case report ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Hypercalcemia is a common electrolyte abnormality in malignancy and is largely caused by activation of parathyroid hormone (PTH) pathways. We report the case of a 76-year-old man with hypercalcemia primarily owing to 1,25-dihydroxyvitamin D3 overproduction from a high-grade fetal lung adenocarcinoma. Histologically, the tumor itself and tumor-adjacent macrophages were positive for the CYP27B1 protein, a key enzyme that generates 1,25-dihydroxyvitamin D3. Suppression was observed in serum PTH and PTH-related hormone levels, suggesting hypercalcemia is independent of the PTH pathway. Serum calcium level returned to normal after surgical resection of the lung cancer, supporting extrarenal overproduction of 1,25-dihydroxyvitamin D3 elicited by the tumors is the cause of hypercalcemia in this patient.
- Published
- 2021
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