USC Institute of Urology
‘Minimal-margin’ Unclamped
Partial Nephrectomy:
Histologic & Anatomic Basis
Raed Azhar, MD MS FRCSC
Clinical Fellow, Robotic Surgery & Advanced Laparoscopy
USC Institute of Urology
USC Institute of Urology
Tumor – Kidney Parenchyma
Interface:
Histologic Analysis
USC Institute of Urology
Patients and Methods: n=124
• H/E slides from 124 Nx/PNx specimens
• Presence of Pseudo-capsule (PC)
• Pseudo-capsule thickness
• Pseudo-capsule invasion by tumor
USC Institute of Urology
Patients and Methods:
• Tumor – parenchyma
• 4 mm2 sectors apportioned at 1, 2, 3, 4 and 5 mm
from tumor edge
• Number and diameter of arterioles
USC Institute of Urology
4 mm2 sectors apportioned at 1, 2, 3, 4 and 5mm from tumor edge
Grade 0-1 = Mild; Grade 2-3 = Severe
Inflammation
Arteriosclerosis
Nephrosclerosis
Glomerulosclerosis
USC Institute of Urology
Results:
• Median tumor size: 3.5 cm
• Malignant: 90%
• 96% of tumors had pseudocapsule
• Median PC thickness: 0.6 mm
• Presence of intra-renal PC
• Cancers: 82%
• Benign: 31% (p<0.001)
• PC invasion:
• Cancers: 45%
• Benign: 15%
(p<0.04)
• pT1a cancers had
intra-renal PC
invasion: 25%
USC Institute of Urology
The closer to the tumor….the smaller the arterioles
USC Institute of Urology
The closer to the tumor….the greater the inflammation, GS, NS, AS
USC Institute of Urology
Conclusions:
•
Most RCCs (82%) have a well-developed intrarenal pseudo-capsule.
•
“Minimal- margin” PN appears histologically
safe… and may result in less blood loss.
•
Care is necessary to avoid positive margins
USC Institute of Urology
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