Splenogonadal Fusion Diagnosed By Tc-99m Heat-Denatured Red Blood Cell Scintigraphy

A 39-year-old man presented with a painless, firm left scrotal mass, pelvic pain. Ultrasound revealed a hypoechoic mass contiguous with the left testis. Given clinical suspicion for splenogonadal fusion (SGF), 99m Tc-labeled heat-denatured red blood cell scintigraphy was ordered and demonstrated radiotracer uptake within the testicular lesion and multiple abdominal foci, confirming ectopic splenic tissue. Although 99m Tc-sulfur colloid scintigraphy is typically used for evaluating splenic tissue, this case illustrates the diagnostic utility of 99m Tc heat-denatured RBC scintigraphy in identifying splenogonadal fusion (SGF).