Splenosis mimicking local recurrence in a case of renal cell carcinoma confirmed using technetium-99m-sulfur colloid scintigraphy and single-photon emission computed tomography/computed tomography

Heterotropic splenic tissue in the renal fossa is characteristically asymptomatic and is usually an incidental finding that has been reported to mimic renal or adrenal tumors. A 50-year-old man with renal cell carcinoma had undergone radical nephrectomy with splenectomy because of the invasion of the splenic capsule. During a follow-up examination, nodules were detected by computed tomography in the subdiaphragmatic region. Although local recurrence was highly suspected, and these masses were diagnosed as ectopic splenic tissues by a technetium-99m-sulfur colloid scintigraphy and unnecessary surgical exploration was avoided.