⁶⁸Ga-PSMA and ⁶⁸Ga-DOTATOC PET/CT imaging mismatch of primary pancreatic adenocarcinoma in prostate cancer patient

Excerpt

A different uptake of ⁶⁸ Ga-PSMA and ⁶⁸ Ga-DOTATOC PET/CT was observed in a hetero-formative hypodense pancreatic lesion (29 mm). These PET/CT scans were performed in a 76-year-old patient with prostate cancer (bilateral acinar adenocarcinoma G3, Gleason score 4 + 4, pT3apN0) after surgery and radiotherapy. A pancreatic mass was incidentally detected at restaging CT, with high levels of PSA. Considering the confounding physiologic uptake of ¹⁸F-Cholin in the pancreatic gland, a restaging ⁶⁸ Ga-PSMA PET/CT demonstrated focal uptakes both in pancreatic lesion and in multiple bone localizations. In the literature, ⁶⁸ Ga-PSMA positivity was reported also in pancreatic NETs [1‐3]. Then, to characterize the pancreatic lesion, ⁶⁸ Ga-DOTATOC PET/CT was performed with no evidence of uptake in the pancreatic mass that, otherwise, showed intense ⁶⁸ Ga-PSMA uptake. At the same time, the laboratory tests detected high levels of CA19.9 (738 U/ml) and CgA (260,7 ng/ml). Finally, to define the nature of the lesion, a biopsy was performed which led to the diagnosis of adenocarcinoma of biliopancreatic origin. We conclude that, even if ⁶⁸ Ga-PSMA PET/CT is currently used in prostate cancer patients [4, 5], several other tumors such as hepatocellular carcinoma (HCC), thyroid, renal cell, and pancreatic cancer can show significant uptake of ⁶⁸ Ga-PSMA [1‐3, 6]. The finding of ⁶⁸ Ga-PSMA uptake in pancreatic adenocarcinoma is very rare, since until now we found only one case in the literature [7]. This occasional mismatch between ⁶⁸ Ga-PSMA and ⁶⁸ Ga-DOTATOC PET/CT can be considered a very curious observation that should draw the attention of the physicians in the interpretation of pancreatic masses in patients with prostatic cancer. …