Complete 68Ga-DOTATATE/PSMA PET/CT Discordance Documented in Metastatic Ileal Neuroendocrine Tumor

In a novel case report from Samsun, Dr. Fatih Batı and Dr. Nilüfer Bıçakcı describe a striking imaging discrepancy in a 40-year-old man with metastatic ileal neuroendocrine tumor (NET). While 68Ga-DOTATATE PET/CT revealed intense somatostatin receptor–mediated uptake in the primary ileal lesion and extensive liver metastases (SUVmax ≈ 15), a contemporaneous 68Ga-PSMA PET/CT scan showed no abnormal tracer accumulation in any disease sites—even though lesion size and burden were identical.

This unexpected finding underscores the heterogeneity of PSMA expression across NET subtypes and suggests that midgut carcinoids may lack the neovasculature–associated PSMA targets seen in other NET classes, such as pancreatic tumors. Importantly, the patient had no history of prostate malignancy, confirming that the absence of PSMA avidity reflected true biological discordance rather than competing tracer dynamics.

Key takeaways from this report include:

• 68Ga-DOTATATE PET/CT remains the definitive imaging modality for staging and restaging of well-differentiated midgut NETs.
• 68Ga-PSMA PET/CT may yield false-negative results in non-prostatic tumors, particularly midgut NETs lacking PSMA expression.
• Therapeutic and diagnostic algorithms for NETs should continue to prioritize somatostatin receptor imaging and interpret PSMA PET findings with caution.

How to Cite
Batı F, Bıçakcı N. Rare discordance between 68Ga-DOTATATE and 68Ga-PSMA PET/CT in a metastatic ileal neuroendocrine tumor: a case report and literature review. TheJODTi. 2025;1(1):11–15.