Iron Polymaltose Infusion Effects on Bone Scintigraphy and Remodeling.

Area of Science:

• Nuclear Medicine
• Oncology
• Endocrinology

Background:

• Bone scintigraphy using 99mTc-HDP is a standard imaging technique for evaluating skeletal metastases.
• Patients with metastatic breast cancer often undergo bone scans to monitor disease progression.

Observation:

• A 73-year-old woman with metastatic breast cancer presented with atypical bone scintigraphy findings.
• Delayed images showed markedly reduced bony uptake, increased renal activity, and soft tissue accumulation of 99mTc-HDP.
• These findings contrasted with previous scans showing appropriate skeletal uptake.

Findings:

• The patient had received intravenous iron polymaltose 22 hours prior to the bone scan.
• The observed scintigraphic changes are hypothesized to be secondary to transiently reduced bone resorption.
• Increased fibroblast growth factor 23 (FGF23) release due to IV iron supplementation is proposed as the underlying mechanism.

Implications:

• Clinicians should consider recent IV iron administration when interpreting bone scintigraphy in patients with metastatic cancer.
• This phenomenon highlights a potential imaging artifact that could lead to misinterpretation of metastatic disease.
• Further research is warranted to elucidate the precise relationship between iron supplementation, FGF23, and bone metabolism in nuclear imaging.