Differential Diagnosis for Filling Defect in the Kidney on CT Urogram
Single Most Likely Diagnosis
- Renal Cell Carcinoma: This is a common cause of a filling defect in the kidney, especially if the defect is solid and enhances with contrast. Renal cell carcinoma is a primary malignancy of the kidney that can present as a mass lesion.
Other Likely Diagnoses
- Blood Clot: A blood clot within the renal collecting system can cause a filling defect on CT urogram. This could be due to trauma, infection, or other causes of bleeding.
- Papillary Necrosis: This condition involves necrosis of the renal papillae, which can cause a filling defect in the kidney. It is often associated with diabetes, analgesic abuse, or sickle cell disease.
- Urothelial Carcinoma: Also known as transitional cell carcinoma, this type of cancer can arise from the lining of the renal collecting system and cause a filling defect.
Do Not Miss Diagnoses
- Xanthogranulomatous Pyelonephritis (XGP): Although rare, XGP is a serious condition that can mimic a tumor. It is a form of chronic pyelonephritis associated with long-standing urinary tract obstruction and infection.
- Renal Infarction: A filling defect could represent an area of infarction within the kidney, which is a medical emergency requiring prompt intervention.
Rare Diagnoses
- Renal Lymphoma: Primary or secondary lymphoma involving the kidney can cause a filling defect, although this is relatively rare.
- Metastasis to the Kidney: Metastatic disease to the kidney from other primary sites can also present as a filling defect, but this is less common than primary renal malignancies.
- Malakoplakia: A rare inflammatory condition that can affect the urinary tract and cause filling defects in the kidney.
- Fungal Ball: In immunocompromised patients, a fungal infection can cause a filling defect in the kidney, often associated with obstructive uropathy.