Multimodal Functional Imaging in Tumor-induced Osteomalacia: ⁶⁸Ga-DOTATATE, ¹⁸F-FDG, and ⁶⁸Ga-FAPI PET/CT Findings

Area of Science:

• Endocrinology
• Oncology
• Radiology

Background:

• Tumor-induced osteomalacia is a rare paraneoplastic syndrome characterized by hypophosphatemia and bone pain, stemming from fibroblast growth factor 23 overproduction.
• Fewer than 1,000 cases are documented, making diagnosis challenging.
• Accurate tumor localization is crucial for effective management.

Purpose of the Study:

• To present the utility of advanced positron emission tomography (PET) imaging in localizing the causative tumor in a patient with tumor-induced osteomalacia.
• To demonstrate the combined use of gallium-68 (⁶⁸Ga)-DOTATATE, ⁶⁸Ga-fibroblast, and ¹⁸F-fluorodeoxyglucose PET in identifying the tumor.

Main Methods:

• Utilized a combination of three PET imaging modalities: ⁶⁸Ga-DOTATATE, ⁶⁸Ga-fibroblast, and ¹⁸F-fluorodeoxyglucose.
• These functional imaging techniques were employed for precise tumor localization in a patient diagnosed with tumor-induced osteomalacia.

Main Results:

• The integrated PET imaging approach successfully identified the tumor responsible for fibroblast growth factor 23 overproduction.
• Specific findings from each modality contributed to the definitive localization, underscoring their complementary roles.

Conclusions:

• Advanced PET imaging, including ⁶⁸Ga-DOTATATE, ⁶⁸Ga-fibroblast, and ¹⁸F-fluorodeoxyglucose, is highly effective for tumor localization in tumor-induced osteomalacia.
• This case highlights the importance of multimodal functional imaging in diagnosing and managing rare paraneoplastic syndromes.