Utility of Multimodality Approach Including Systemic FGF23 Venous Sampling in Localizing Phosphaturic Mesenchymal Tumors.

Abstract

Context:

Tumor-induced osteomalacia (TIO) is one of the most common forms of acquired fibroblast growth factor 23 (FGF23)-related hypophosphatemia and is usually caused by phosphaturic mesenchymal tumors (PMTs). Although the complete resection of PMTs can cure TIO, preoperative localization of tumors by standard imaging modalities is often challenging. In addition to 18F-fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography (FDG-PET) and 111In-pentetreotide scintigraphy (SRS), systemic FGF23 venous sampling (FGF23VS) has been used to help localize PMTs in specialized institutions.

Objective:

This study aimed to evaluate the diagnostic performance of each imaging test and their combinations in localizing PMTs.

Methods:

In an observational retrospective study of patients with adult-onset FGF23-related osteomalacia who underwent all 3 imaging studies (FDG-PET, SRS, and FGF23VS), the rate of successful preoperative localization of the tumors was evaluated only in the patients with pathological diagnoses of PMTs, considering the possibility that pathogenesis of patients without identified tumors might be due to other causes such as late-onset hereditary FGF23-related hypophosphatemia.

Results:

A total of 30 Japanese patients with TIO (median age, 60 years [range, 28-87 years]; 10 women [33.3%]) were included in the study. The success rate of preoperative localization for each test and combinations of 2 or 3 tests among 18 patients with PMTs was as follows: 72% (FDG-PET), 72% (SRS), 94% (FGF23VS), 89% (FDG-PET, SRS), 100% (FDG-PET, FGF23VS), 94% (SRS, FGF23VS), and 100% (FDG-PET, SRS, and FGF23VS).

Conclusion:

We observed the highest localization rate of PMTs in patients with identified PMTs with the combination of FDG-PET and FGF23VS.

• Authors: Hajime Kato, Minae Koga, Yuka Kinoshita, Naoko Hidaka, Yoshitomo Hoshino, Yuichi Takashi, Makoto Arai, Hiroshi Kobayashi, Masaki Katsura, Yuji Nakamoto, Naohiro Makise, Tetsuo Ushiku, Kazuto Hoshi, Masaomi Nangaku, Noriko Makita, Seiji Fukumoto, Nobuaki Ito
• Journal: Journal of the Endocrine Society (J Endocr Soc) Vol. 7 Issue 2 Pg. bvac181 (Dec 15 2022) ISSN: 2472-1972 [Electronic] United States
• PMID: 36540156 (Publication Type: Journal Article)
• Copyright: © The Author(s) 2022. Published by Oxford University Press on behalf of the Endocrine Society.