PSMA PET/CT Detects Hürthle Cell Variant Papillary Thyroid Carcinoma After Lu-177 PSMA Therapy

In a concise case report from Dr. Adem Maman at Atatürk University Faculty of Medicine, Ga-68 PSMA PET/CT—used to monitor response to Lu-177 PSMA radioligand therapy for metastatic prostate adenocarcinoma—unexpectedly revealed a secondary thyroid malignancy.

A 70-year-old man with extensive PSMA-avid prostate and skeletal lesions underwent baseline PET/CT, which also identified a 12 × 14 mm left thyroid nodule exhibiting modest tracer uptake (SUVmax 4.2). Following six cycles of Lu-177 PSMA therapy, during which nearly all known metastases resolved, a routine follow-up scan demonstrated a striking increase in PSMA accumulation within the same nodule (SUVmax 12.5), with no other sites of abnormal activity.

Ultrasound-guided fine-needle aspiration was then performed, and histopathologic analysis confirmed a Hürthle cell variant of papillary thyroid carcinoma. Definitive management comprised total thyroidectomy, followed by radioiodine ablation to eradicate residual thyroid tissue. At 12-month follow-up, both PET/CT and ultrasound showed no evidence of recurrence, underscoring the dual utility of PSMA PET/CT in both theranostic treatment monitoring and incidental malignancy detection.

Key takeaways from this report include:

• PSMA PET/CT can unmask non-prostatic cancers when tracer affinity increases after Lu-177 PSMA therapy.
• Any new or intensified PSMA uptake outside known disease sites warrants prompt histopathologic evaluation.
• Theranostic imaging offers comprehensive surveillance—guiding both assessment of treatment response and detection of unexpected lesions.

How to Cite
Maman A. Detection and implications of increased PSMA uptake in thyroid nodule following Lu-177 PSMA therapy: a case of Hürthle cell variant thyroid papillary carcinoma identified by Ga-68 PSMA PET/CT. TheJODTi. 2025;1(1):8–10.