¹⁸F-PSMA-1007 PET/CT uptake in multiple angiolipomas caused by PSMA expression in capillaries: a case report

Prostate specific membrane antigen (PSMA) is a transmembrane glycoprotein that was originally cloned in the membrane of prostate gland epithelial cells. It has been confirmed to be highly expressed in prostate cancer cells, and in some non-prostatic tissues, including the brain and some benign lesions. PSMA-based imaging has been extensively used for the assessment of prostate carcinoma. The high uptake of PSMA imaging in these non-prostate cancer lesions may lead to some misdiagnosis. It is of important clinical significance to explore the possible causes of high PSMA uptake in these lesions. Here, we present a case of a 77-year-old man with prostate carcinoma who underwent a whole-body ¹⁸F-PSMA-1007 positron emission tomography/computed tomography (PET/CT) scan for staging. The results of the scan showed intense tracer uptake in both the prostatic bed and in multiple subcutaneous lesions. The subcutaneous lesions were later found to be angiolipomas by histopathological examination. Immunohistochemistry demonstrated strong positive cytoplasmic PSMA staining in lesional prostate cancer cells in prostate carcinoma, and mild-to-moderate positive cytoplasmic capillary PSMA staining in angiolipoma fatty density nodules. Our case report therefore demonstrated that ¹⁸F-PSMA-1007 PET/CT uptake in multiple angiolipomas was caused by PSMA expression in capillaries, and further knowledge of PSMA expression in benign lesions may be critical to minimize false-positive findings with ¹⁸F-PSMA-1007 PET/CT imaging.