Diagnostic dilemma of ectopic pelvic kidney in planar skeletal and renal cortical scintigraphy resolved by SPECT/CT

We present a 55-year old male patient who was subjected to whole body skeletal scintigraphy for metastatic work up of urinary bladder cancer. Whole body 99mTc-methylene diphosphonate (MDP) skeletal scintigraphy was performed. That revealed no skeletal metastasis in the entire body skeleton and normally visualized left kidney with empty right renal fossa. Additionally tracer activity collected in pelvic region giving impression of ectopically placed kidney. To rule out ectopic pelvic kidney 99mTc-DMSA (Di-mercaptosuccinic acid) renal cortical imaging was performed. The cortical scintigraphy revealed bean shape tracer activity in pelvis simulating kidney, in addition to normal left kidney. However faint tracer activity is also localized in the right renal fossa. To differentiate malfunctioning kidney, gall bladder or intestinal tracer activity Single photon emission tomography/computed tomography (SPECT/CT) was acquired and images revealed abnormal tracer collection in pelvis was a localized urinary tracer activity in bladder and right kidney was small with impaired function.