FGF-23 transmitted tumor - induced hypophosphatemic osteomalacia: A rare case of a young woman with recurrent fractures and review of the literature

Florian A Frank; Lukas Gerber; Alexander Cornelius; Daniel Baumhoer; Andreas H Krieg

doi:10.1016/j.jbo.2022.100413

FGF-23 transmitted tumor - induced hypophosphatemic osteomalacia: A rare case of a young woman with recurrent fractures and review of the literature

J Bone Oncol. 2022 Jan 29:33:100413. doi: 10.1016/j.jbo.2022.100413. eCollection 2022 Apr.

Authors

Florian A Frank¹, Lukas Gerber², Alexander Cornelius³, Daniel Baumhoer⁴, Andreas H Krieg⁵

Affiliations

¹ Department of Orthopaedic and Trauma Surgery, Kantonsspital Aarau, Tellstrasse 25, Aarau 5001, Switzerland.
² Department of Nephrology, Dialysis and Transplantation, Kantonsspital Aarau, Tellstrasse 25, Aarau 5001, Switzerland.
³ Department of Radiology, Kantonsspital Aarau, Tellstrasse 25, Aarau 5001, Switzerland.
⁴ Bone Tumor Reference Center at the Institute of Medical Genetics and Pathology, University Hospital Basel and University of Basel, Spitalstrasse 21, Basel 4031, Switzerland.
⁵ Bone and Soft Tissue Tumor Center of the University of Basel (KWUB), Spitalstrasse 33, Basel 4056, Switzerland.

Abstract

We present a case of tumor-induced osteomalacia (TIO) in a young woman of 22 years. The fibroblast growth factor 23 transmitting tumor in her left foot remained undetected for several years. She suffered several fractures including insufficiency fractures of both femoral necks requiring bilateral proximal femoral nailing. After phosphaturia was diagnosed any known genetic etiology was excluded. Even advanced imaging modalities were unable to detect the clinically silent tumor until an ⁶⁸Ga-DOTA-TOC-PET/CT-scan revealed a mass with paraneoplastic activity in the left foot. Complete resection of the tumor proved to cure her condition after 9 years of uncertainty and suffering. Serum phosphate levels returned to normal within days. After presentation of the case report, the current literature on published cases of TIO between 1956 and 2021 is summarized to emphasize the importance of an accurate and early diagnosis. Our case report aims to illustrate that a long latency period of diagnosis may be avoided utilizing the latest imaging techniques to spare affected patients from long treatment of symptoms instead of finding the underlying cause.

Keywords: 68Ga-DOTA-TOC-PET/CT-scan; 68Ga-DOTA-TOC-PET/CT-scan, 8Ga-DOTA(0)-Phe(1)-Tyr(3)-octreotide positron emission tomography/computed tomography; FDG-PET, Fluorodeoxyglucose positron emission tomography; FGF 23; FGF, fibroblast growth factor; PTH, parathyroid hormone; Phosphaturic tumor; TIO, tumor-induced osteomalacia; TIR, tumor-induced hypophosphatemic rickets; Tumor-induced osteomalacia.

Publication types

Case Reports