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.
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 "lomangioma" 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.
Orthopedic Department, Chinese PLA General Hospital, Beijing 100853, P. R. China.
Fang-Ke
FK
Hu
Fang
F
Yuan
Cheng-Ying
CY
Jiang
Da-Wei
DW
Lv
Bei-Bei
BB
Mao
Qiang
Q
Zhang
Zeng-Qiang
ZQ
Yuan
Yan
Y
Wang
D001859:Bone Neoplasms / Q000097:blood / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000097:blood*; D005500:Follow-Up Studies; D006801:Humans; D017674:Hypophosphatemia / Q000097:blood / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology / Q000601:surgery; D008637:Mesenchymoma / Q000097:blood / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D050279:Metacarpal Bones; D008875:Middle Aged; D009372:Neoplasms, Connective Tissue / Q000097:blood / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D010018:Osteomalacia / Q000097:blood / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology* / Q000601:surgery; D010257:Paraneoplastic Syndromes; D010710:Phosphates / Q000097:blood; D011859:Radiography
C000717427:FGF23 protein, human; D010710:Phosphates; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23