What is splenogonadal fusion, and what are its US imaging features?
Splenogonadal fusion is a rare anomaly where accessory splenic tissue is found in the scrotum, more commonly on the left than right side, which may be fused to the testicle or other surrounding structures. In some cases, a connection with the spleen is maintained via a cord of splenic or fibrous tissue.
On US, a homogeneous hypoechoic testicular lesion is usually seen, which is generally indistinguishable from a testicular neoplasm. A pattern of central blood flow with peripheral branching on Doppler US may suggest this particular diagnosis. A definitive diagnosis may be established through use of a technetium-99m ( 99m Tc) heat-denatured red blood cell (RBC) scan or a 99m Tc sulfur colloid scan, as the splenic tissue will demonstrate uptake of these radiotracers.
