[Supernumerary spleen simulating a renal tumor. Case report].

Area of Science:

• Radiology
• Pathology
• Surgical Oncology

Background:

• Ectopic spleen, a rare condition, can present as a renal mass.
• Accurate differentiation from renal tumors is crucial for appropriate management.

Observation:

• A 54-year-old splenectomized female presented with an incidental left upper pole renal mass on ultrasound.
• CT scan revealed a suspected renal neoplasm, leading to tumorectomy.

Findings:

• Pathologic examination confirmed the mass as a supernumerary spleen, not a renal tumor.
• This case highlights a rare presentation of ectopic splenic tissue.

Implications:

• Splenic pseudotumors should be considered in the differential diagnosis of renal, adrenal, and retroperitoneal masses.
• CT scan is the preferred imaging modality, with gammagraphy as a useful adjunct.
• Conservative management is recommended for asymptomatic splenic pseudotumors.