Unexpected extra-renal uptake of [99mTc]Tc-EC on renal scintigraphy in a patient with renal transplantations

This research reports a case involving a 53-year-old man with a history of two renal transplants, each placed in one of the lower abdominal quadrants nine years apart, who underwent [99mTc]Tc-ethylene dicysteine (EC) dynamic scintigraphy to assess renal function and hydroureteronephrosis. The scintigraphy revealed an unexpected area of increased extra-renal tracer uptake in the lower pelvic region during both blood flow and functional phases of the study. Subsequent single-photon emission computed tomography/computed tomography (SPECT/CT) images localized this uptake to a fracture in the right pubic bone. This case highlights the necessity of recognizing atypical [99mTc]Tc-EC uptake patterns, which can provide critical clinical insights for the interpretation of unusual imaging findings and enhance diagnostic accuracy.