髙士, 祐一 The University of Tokyo
Kinoshita, Yuka The University of Tokyo
Ito, Nobuaki The University of Tokyo
Taguchi, Manabu The University of Tokyo
Takahashi, Masaaki The University of Tokyo
Egami, Naoya The University of Tokyo
Tajima, Shogo The University of Tokyo
Nangaku, Masaomi The University of Tokyo
fibroblast growth factor 23
phosphaturic mesenchymal tumor mixed connective tissue variant
A 77-year-old man was suspected of having tumor-induced osteomalacia (TIO) because of hypophosphatemia (1.9 mg/dL) and elevated serum fibroblast growth factor 23 (FGF23) level (186.9 pg/mL). We detected a tumor in his left parotid gland, and the FGF23 level in the left external jugular vein indicated that the tumor overproduced FGF23. After the removal of the tumor, the serum FGF23 level rapidly decreased, and the serum phosphate normalized. This is the first case of TIO caused by a tumor in a parotid gland. This case indicates that the responsible tumors for TIO can be quite diverse.
The Japanese Society of Internal Medicine
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