Splenogonadal fusion is a rare congenital malformation that results from an abnormal connection between the primitive spleen and gonad during gestation.

[3] The condition remains a diagnostic challenge, but preoperative consideration of the diagnosis and use of ultrasound may help avoid unnecessary orchiectomy.

The spleen derives from mesenchymal tissue and an inappropriate fusion can happen between the gonadal ridge during gut rotation, which occurs between weeks 5 and 8 of fetal life.

There is also postulation that fusion may occur due to adhesion after an inflammatory response or a lack of apoptosis between the structures.

Siblings documented to have splenogonadal fusion and an accessory spleen provides additional evidence of a possible genetic component.

[8] On scrotal ultrasound, ectopic splenic tissue may appear as an encapsulated homogeneous extratesticular mass, isoechoic with the normal testis.

[7] Limitations of doppler ultrasonography include visualizing the nonspecific paratesticular masses which can mimic malignancies such as rhabdomyosarcoma or embryonal sarcoma.

[12] When technetium-99m sulfur colloid scans are not included in a patient's diagnostic workup, the diagnosis is often not made until the surgeon performs an abdominal exploration using laparoscopy which can visualize the splenic tissue grossly.

Surgical approach should attempt to divide the mass and the gonad at the connecting plane for removal of the splenic tissue.