Preoperative tumor localization by means of venous sampling for fibroblast growth factor-23 in a patient with tumor-induced osteomalacia

Westerberg, Per-AntonDepartments of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden (author)

OBJECTIVE: To report on a novel strategy for tumor localization in a 62-year-old man with hypophosphatemic tumor-induced osteomalacia (TIO). METHODS: Repeated computed tomographic and magnetic resonance imaging scans failed to localize any tumor in a patient with adult-onset hypophosphatemic osteomalacia. Therefore, venous sampling for fibroblast growth factor-23 (FGF23)--a circulating hormone that has been identified as a causative factor for TIO--in major veins was conducted. Serum FGF23 was measured from collected samples by an intact FGF23 enzyme-linked immunosorbent assay. RESULTS: Venous sampling suggested a local increase in serum FGF23 in the left femoral vein; this finding prompted performance of octreotide scintigraphy restricted to the left leg. A tumor was located at the lateral condyle of the left femur, which was also confirmed by magnetic resonance imaging. Surgical resection of the tumor normalized the serum phosphorus and 1,25-dihydroxyvitamin D3 levels within 5 to 10 days, and FGF23 declined to normal levels within 24 hours. Histologic analysis supported the diagnosis of a soft-tissue giant cell tumor. CONCLUSION: Our study case demonstrates the diagnostic complexity and difficulties in localizing a small tumor in a patient with TIO. Venous sampling for FGF23 may be helpful in tumor localization in sporadic cases of hypophosphatemic osteomalacia, especially when noninvasive diagnostic techniques prove insufficient.

Olauson, HannesDepartments of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden (author)
Toss, GöranÖstergötlands Läns Landsting,Linköpings universitet,Internmedicin,Hälsouniversitetet,Endokrin- och magtarmmedicinska kliniken US(Swepub:liu)gorto76 (author)
Wikström, BjörnDepartments of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden (author)
Morales, OllalloÖstergötlands Läns Landsting,Linköpings universitet,Institutionen för medicin och hälsa,Hälsouniversitetet,Röntgenkliniken i Linköping (author)
Linde, Torbjörn,1957-Uppsala universitet,Institutionen för medicinska vetenskaper,Departments of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden(Swepub:uu)torblind (author)
Jonsson, KennethDepartments of Surgical Science, Uppsala University Hospital, Uppsala, Sweden (author)
Ljunggren, ÖstenDepartments of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden (author)
Larsson, Tobias E.Departments of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden (author)
Departments of Medical Sciences, Uppsala University Hospital, Uppsala, SwedenInternmedicin (creator_code:org_t)

By the author/editor: Westerberg, Per- ...; Olauson, Hannes; Toss, Göran; Wikström, Björn; Morales, Ollallo; Linde, Torbjörn, ...; show more...; Jonsson, Kenneth; Ljunggren, Östen; Larsson, Tobias ...; show less...

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