Presentation
Painless hematuria.
Patient Data
Malrotated right kidney with abnormal, thickened enhancing soft tissue within the renal pelvis and proximal ureter. Simple renal cysts in both kidneys. No lymphadenopathy.
The patient proceeded to nephrectomy.
Histology:
MACROSCOPIC DESCRIPTION: A kidney (273g, 105x45x45mm) with ureter (130mm length, 8mm diameter), renal vein (up to 20mm), renal anterior (up to 15mm) and perinephric fat (up to 30mm). Arising within the renal pelvis and extending into a calyx is a friable tan-brown exophytic tumor 45x30x4mm. Tumor does not appear to invade the pelvic wall or renal parenchyma and is clear of the perinephric margin by 3mm. Tumor appears to extend down proximal ureter to a distance of 20mm. A renal cortical cyst up to 12mm is present.
MICROSCOPIC DESCRIPTION: Sections of kidney show a tumor arising from the renal pelvis, comprising large papillae lined by thickened urothelium showing minor nuclear crowding, enlargement and loss of nuclear polarity. Tumor extends into proximal ureter and involves a renal calyx. Invasion is not identified. Tumor is clear of the perinephric, ureteric and vascular margins. A simple benign cortical cyst is present, which is lined by bland flattened epithelium. Renal parenchyma away from the capsule and tumor shows mild intimal fibroelastosis of small arteries but is otherwise normal.
DIAGNOSIS: Non-invasive low grade papillary urothelial carcinoma, a rising from renal pelvis.
Case Discussion
This case serves as a reminder that pathology can definitely arise in normal variants!