FDG-Avid Hürthle Cell Thyroid Adenoma

Area of Science:

• Nuclear Medicine
• Oncology
• Endocrinology

Background:

• Fluorodeoxyglucose Positron Emission Tomography (FDG PET) is utilized for staging and monitoring nonthyroidal malignancies.
• Incidental thyroid uptake on FDG PET occurs in ~2.5% of patients, with a significant proportion representing malignancy.

Observation:

• A 50-year-old woman, evaluated for heart transplantation and with a history of breast cancer, presented with a large, intensely FDG-avid thyroid mass on PET/CT.
• Histopathological and molecular analysis confirmed the thyroid mass to be a Hürthle cell adenoma.

Findings:

• Hürthle cell neoplasms can exhibit very high FDG avidity, mimicking malignant thyroid lesions on PET imaging.
• This finding expands the differential diagnosis for hypermetabolic thyroid nodules detected incidentally.

Implications:

• Clinicians should consider Hürthle cell neoplasms in the differential diagnosis of intensely FDG-avid thyroid incidentalomas.
• This case underscores the importance of careful evaluation of thyroid incidentalomas, regardless of patient history.
• Further research may elucidate specific imaging characteristics or molecular markers to differentiate benign from malignant Hürthle cell neoplasms.