title: Oncogenic osteomalacia caused by an occult paranasal sinus tumor.
abstract: Oncogenic osteomalacia (OOM) is a rare bone disease characterized by inadequate bone mineralization and is caused by a humoral factor mainly produced by benign mesenchymal tumors. We report a case of OOM caused by an occult phosphaturic mesenchymal tumor in the paranasal sinus. The causative tumor was small and localized in the ethmoid sinus, and the patient did not exhibit any nasal symptoms. 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) depicted the location of the occult tumor, and systemic venous sampling followed by assessments of the samples' fibroblast growth factor 23 (FGF23) concentrations confirmed that the tumor secreted FGF23. The tumor was resected via an external surgical approach, resulting in the complete relief of the patient's symptoms. The combination of FDG-PET and systemic venous sampling to assess serum FGF23 levels is useful for identifying small asymptomatic OOM-associated tumors. Such tumors are rare, but a significant proportion of them develop in the head and neck region, and complete resection is the most effective treatment. It is important that ENT surgeons are aware of the characteristics of OOM.
authors: Department of Otorhinolaryngology - Head and Neck Surgery, Gunma University, Japan. Electronic address: okamy@gunma-u.ac.jp.
authors: Tomofumi
authors: T
authors: Okamiya
authors: Department of Otorhinolaryngology - Head and Neck Surgery, Gunma University, Japan.
authors: Katsumasa
authors: K
authors: Takahashi
authors: Gunma Medical Career Center, Gunma University Hospital, Japan.
authors: Hideo
authors: H
authors: Kamada
authors: Department of Pathology, Gunma University Hospital, Japan.
authors: Junko
authors: J
authors: Hirato
authors: Department of Pathology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, Japan.
authors: Toru
authors: T
authors: Motoi
authors: Division of Nephrology and Endocrinology, Department of Medicine, University of Tokyo Hospital, Japan.
authors: Seiji
authors: S
authors: Fukumoto
authors: Department of Otorhinolaryngology - Head and Neck Surgery, Gunma University, Japan.
authors: Kazuaki
authors: K
authors: Chikamatsu
mesh_terms: D000328:Adult; D005005:Ethmoid Sinus / Q000000981:diagnostic imaging*; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000378:metabolism; D006801:Humans; D009372:Neoplasms, Connective Tissue / Q000000981:diagnostic imaging*; D010018:Osteomalacia; D010255:Paranasal Sinus Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism; D010257:Paraneoplastic Syndromes; D049268:Positron-Emission Tomography
chemical_list: C000717427:FGF23 protein, human; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23
keywords: FDG-PET; FGF23; Oncogenic osteomalacia; Systemic venous sampling