Uptake of 68Ga–Prostate-Specific Membrane Antigen PET in Adrenal Gland

Abstract

A 76-year-old man with prostate cancer pT2c N0 M0 R1 GS9 (4+5) operated 2009 and radiated postoperatively underwent restaging by Ga-PSMA-PET in January 2017 because of PSA rise at 0.44 ng/ml under medication with GnRH analogues. An intense focal uptake of the diffusely enlarged left adrenal gland was observed as the only pathological finding. Further evaluation by MRI imaging revealed a plump left adrenal gland with a relatively enlarged diameter of 2 cm and excluded tumor and nodular hyperplasia as well. Without any change of the therapeutic regime the patient presented in July 2017 with a PSA level of 0.05 ng/ml and no sign of cancer progress.

Increased Uptake of 18F-PSMA-1007 in Corpus Luteum Demonstrated by PET/CT

“…Previous studies have also shown PSMA expression in normal (nonmalignant) tissue including the ovary (stromal cells) and other organs, such as normal prostate, bladder, kidney, testis, fallopian tube, endometrium, breast, adrenal gland, liver, esophagus, stomach, small intestine, colon, and brain. [5][6][7][8] Neovasculature within tumors also overexpresses PSMA and is a known cause for increased tumoral uptake, so a contribution of PSMA expression due to neovasculature within the corpus luteum cannot be excluded. Corpora lutea can show an increased uptake of PSMA-targeting tracers, and this entity should be recognized when women are scanned, which will become more frequent as PSMA is a clinically validated theranostics target, with extension of its use to tumoral entities also occurring in women (adenoid cystic tumors, salivary gland tumor, etc).…”

“…On the other hand, we found intense 18 F-PSMA-1007 uptake in the left ovary (SUV max , 30.1; arrow), compatible with a corpus luteum on CT. 18 F-FDG uptake within corpora lutea is a well-known pitfall in gynecologic and genitourinary oncologic imaging, 3,4 but to our knowledge, physiologically increased uptake of PSMA-targeting tracers in corpora lutea has not been reported. Previous studies have also shown PSMA expression in normal (nonmalignant) tissue including the ovary (stromal cells) and other organs, such as normal prostate, bladder, kidney, testis, fallopian tube, endometrium, breast, adrenal gland, liver, esophagus, stomach, small intestine, colon, and brain 5–8 . Neovasculature within tumors also overexpresses PSMA and is a known cause for increased tumoral uptake, so a contribution of PSMA expression due to neovasculature within the corpus luteum cannot be excluded.…”

68Ga-PSMA-11 PET/CT in Isolated Bilateral Adrenal Metastases From Prostate Adenocarcinoma

“…This case demonstrates the usefulness of 68 Ga-PSMA PET/CT in identifying atypical metastasis from prostate adenocarcinoma and its contribution for an accurate restaging 5,6 . Care should be taken, however, when interpreting the findings because other adrenal disorders, such as adrenocortical carcinoma 7,8 and adrenal adenoma, 9,10 can show increased PSMA uptake. PSMA uptake by nonprostatic disorders is in general not as high as PSMA uptake by metastatic prostate adenocarcinoma 5,11,12 .…”

The utility of radiolabeled PSMA ligands for tumor imaging

“…They administrated 200 MBq of 68 Ga-PSMA-HBED-CC to patient. PET/CT showed intense uptake of 68 Ga-PSMA in left adrenal gland as the only abnormal finding (Strele-Trieb et al, 2018).…”