Bladder hernia in the inguinal canal mimicking pubic metastasis on [99mTc]Tc-MDP and [99mTc]Tc-HYNIC-PSMA whole body scans

A 73 y/o male with first presentation of urinary retention from two months ago referred to our department by an urologist for prostate cancer staging. The patient had gleason score of 5+4 and total PSA of 79. He underwent [99mTc]Tc-MDP and [99mTc]Tc-HYNIC-PSMA scans on two different days. The bone study revealed diffuse uptake in sacrum and a focus of abnormal [99mTc]Tc-MDP activity in the right SI joint. Another focus was also noted in right pubic region best seen on anterior projection which later on SPECT/CT was confined to a bladder diverticulum with tracer accumulation protruding into the right inguinal canal forming a hernial sac. Following a few days, [99mTc]Tc-HYNIC-PSMA scan was carried out and depicted high uptake in sacrum and right pubic region as well. The uptake was again localized to the bladder hernia on dedicated SPECT/CT acquisition. The findings denotes an important differential diagnosis of the pubic metastases as well as added value of SPECT/CT imaging in aforementioned scans.