title: Reports of 17 Chinese patients with tumor-induced osteomalacia.
abstract: Tumor-induced osteomalacia (TIO) is a rare acquired form of hypophosphatemic osteomalacia, which is usually attributed to the overproduction of fibroblast growth factor 23 (FGF-23) by benign mesenchymal neoplasms. Localization and thereafter surgical resection of tumors lead to a cure. The present study aimed to investigate the clinical data, diagnostic methods, and follow-up after tumor resection at one medical center in Shanghai to characterize the profile of this rare disorder and to share our successful experience in diagnosis and treatment. Twenty-three patients with adult-onset hypophosphatemia osteomalacia seen in Shanghai Sixth People's Hospital from 2009 to 2014 and 95 normal individuals were enrolled. After taking a medical history and performing a physical examination, we analyzed the laboratory results (including the serum FGF-23 levels) and localized the tumors by18F-fluorodeoxyglucose positron emission tomography and computed tomography (18F-FDG PET/CT),99mTc-octreotide (99mTc-OCT) scintigraphy, and magnetic resonance imaging (MRI). On the basis of the results of laboratory tests and imaging findings, tumor resection was conducted in 17 patients with a certain diagnosis of TIO. The results demonstrated that the 17 patients (nine men and eight women, average age 46.6 ± 12.9 years) had TIO. FGF-23 level was elevated in 94.1 % of patients (16 of 17 patients) . Serum phosphorus level decreased in 100 % of patients.18F-FDG PET/CT revealed five tumors,99mTc-OCT scintigraphy revealed two tumors, physical examination revealed nine tumors, and MRI revealed one tumor, among which 58.8 % of the causative tumors (10 of 17 tumors) were located in the lower extremities. After tumor resection, serum phosphorus levels normalized in 100 % of patients (all 17 patients) in 4-21 days and FGF-23 levels decreased in 90 % of patients (nine of ten patients). We found 64.7 % of the tumors (11 of 17 tumors) were phosphaturic mesenchymal tumors or a phosphaturic mesenchymal tumor mixed connective tissue variant. Measurement of serum phosphorus and FGF-23 levels in patients with suspected TIO is of paramount importance for diagnosing of TIO.18F-FDG PET/CT,99mTc-OCT scintigraphy, and physical examination play a considerable role in revealing TIO-associated tumors. TIO-associated tumors were more frequently located in the lower extremities than in other places; thus, the lower extremities need to be carefully checked. Complete surgical resection results in normalization of parameters in laboratory tests and relief of symptoms of TIO patients.
authors.affiliation: Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Diseases, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yi-Shan Rd, Shanghai, 200233, People's Republic of China.
authors.forename: Wei-Jia
authors.initials: WJ
authors.lastname: Yu
authors.affiliation: Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Diseases, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yi-Shan Rd, Shanghai, 200233, People's Republic of China.
authors.forename: Jin-Wei
authors.initials: JW
authors.lastname: He
authors.affiliation: Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Diseases, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yi-Shan Rd, Shanghai, 200233, People's Republic of China.
authors.forename: Wen-Zhen
authors.initials: WZ
authors.lastname: Fu
authors.affiliation: Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Diseases, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yi-Shan Rd, Shanghai, 200233, People's Republic of China. chunwang66@gmail.com.
authors.forename: Chun
authors.initials: C
authors.lastname: Wang
authors.affiliation: Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Diseases, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yi-Shan Rd, Shanghai, 200233, People's Republic of China. zzl2002@medmail.com.cn.
authors.forename: Zhen-Lin
authors.initials: ZL
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D000469:Alkaline Phosphatase / Q000097:blood; D044466:Asian People / Q000235:genetics*; D002681:China; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009372:Neoplasms, Connective Tissue / Q000097:blood / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D015282:Octreotide / Q000031:analogs & derivatives / Q000737:chemistry; D015609:Organotechnetium Compounds / Q000737:chemistry; D010018:Osteomalacia; D010257:Paraneoplastic Syndromes; D010758:Phosphorus / Q000097:blood; D000072078:Positron Emission Tomography Computed Tomography; D055815:Young Adult
chemical_list: C493098:99mTc-octreotide; C000717427:FGF23 protein, human; D015609:Organotechnetium Compounds; D010758:Phosphorus; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23; D000469:Alkaline Phosphatase; D015282:Octreotide
keywords: 18F-Fluorodeoxyglucose positron emission tomography and computed tomography; Fibroblast growth factor 23; Tumor-induced osteomalacia