Tumor-induced osteomalacia with elevated fibroblast growth factor 23： a case of phosphaturic mesenchymal tumor mixed with connective tissue variants and review of the literature

• Published in: Ai zheng Vol. 30; no. 11; pp. 794 - 804
• Main Authors: Hu, Fang-Ke, Yuan, Fang, Jiang, Cheng-Ying, Lv, Da-Wei, Mao, Bei-Bei, Zhang, Qiang, Yuan, Zeng-Qiang, Wang, Yan
• Format: Journal Article
• Language: English
• Published: England Medical College, Nankai University,Tianjin 300071, P. R. China%Orthopedic Department, Chinese PLA General Hospital, Beijing 100853, P. R. China 01.11.2011; Orthopedic Department, Chinese PLA General Hospital, Beijing 100853, P. R. China; institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, P. R. China%Medical College, Nankai University,Tianjin 300071, P. R. China%Orthopedic Department, Chinese PLA General Hospital, Beijing 100853, P. R. China%institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, P. R. China; Sun Yat-sen University Cancer Center
• Subjects: Bone Neoplasms - blood; Bone Neoplasms - complications; Bone Neoplasms - diagnostic imaging; Bone Neoplasms - pathology; Bone Neoplasms - surgery; Case Research; Female; Fibroblast Growth Factors - blood; Follow-Up Studies; Humans; Hypophosphatemia - blood; Hypophosphatemia - diagnostic imaging; Hypophosphatemia - etiology; Hypophosphatemia - pathology; Hypophosphatemia - surgery; Mesenchymoma - blood; Mesenchymoma - complications; Mesenchymoma - diagnostic imaging; Mesenchymoma - pathology; Mesenchymoma - surgery; Metacarpal Bones; Middle Aged; Neoplasms, Connective Tissue - blood; Neoplasms, Connective Tissue - complications; Neoplasms, Connective Tissue - diagnostic imaging; Neoplasms, Connective Tissue - pathology; Neoplasms, Connective Tissue - surgery; Osteomalacia - blood; Osteomalacia - diagnostic imaging; Osteomalacia - etiology; Osteomalacia - pathology; Osteomalacia - surgery; Phosphates - blood; Radiography; 变种; 复习; 成纤维细胞生长因子; 手术切除; 混合; 结缔组织; 肿瘤; 软骨病; hypophosphatemia; Tumor-induced osteomalacia (TIO); fibroblast growth factor 23 (FGF23); phosphaturic mesenchymal tumors mixed connective tissue variants (PMTMCT)
• ISSN: 1000-467X; 1944-446X
• DOI: 10.5732/cjc.011.10013

Tumor-induced osteomalacia （TIO）, or oncogenic osteomalacia （OOM）, is a rare acquired paraneoplastic disease characterized by renal phosphate wasting and hypophosphatemia. Recent evidence shows that tumor-overexpressed fibroblast growth factor 23 （FGF23） is responsible for the hypophosphatemia and osteomalacia. The tumors associated with TIO are usually phosphaturic mesenchymal tumor mixed connective tissue variants （PMTMCT）. Surgical removal of the responsible tumors is clinically essential for the treatment of TIO. However, identifying the responsible tumors is often difficult. Here, we report a case of a TIO patient with elevated serum FGF23 levels suffering from bone pain and hypophosphatemia for more than three years. A tumor was finally located in first metacarpal bone by octreotide scintigraphy and she was cured by surgery. After complete excision of the tumor, serum FGF23 levels rapidly decreased, dropping to 54.7% of the preoperative level one hour after surgery and eventually to a little below normal. The patient＇s serum phosphate level rapidly improved and returned to normal level in four days. Accordingly, her clinical symptoms were greatly improved within one month after surgery. There was no sign of tumor recurrence during an 18-month period of follow-up. According to pathology, the tumor was originally diagnosed as ＂glomangioma＂ based upon a biopsy sample, ＂proliferative giant cell tumor of tendon sheath＂ based upon sections of tumor, and finally diagnosed as PMTMCT by consultation one year after surgery. In conclusion, although an extremely rare disease, clinicians and pathologists should be aware of the existence of TIO and PMTMCT, respectively.