Definition
• known as Hypertrophic or enlarged column of
Bertin, junctional parenchyma, lobar dysmorphism, renal pseudotumor, renal septum,
septal cortex, focal cortical hyperplasia, benign cortical rest
Definitions
• Hypertrophic band of normal cortical tissue
that separates pyramids of renal medulla
Location
○ At junction of upper and middle 1/3 of kidney
○ Left side > right side
○ Unilateral > bilateral (18% of cases)
Size
○ Less than 3 cm
Ultrasonographic Findings
• Grayscale ultrasound
○ Homogenous round lesion isoechoic to renal
cortex
○ Extends between renal pyramids
○ Normal renal contour
○ Bordered by echogenic junctional parenchymal
line and echogenic triangular junctional parenchymal defect
○ Indentation of renal sinus laterally
○ Echogenicity may be increased because of
anisotropy
• Color Doppler
○ Normal perfusion indicating normal renal
tissue
○ No vascular distortion with preserved arcuate
arteries surrounding pyramids
○ No abnormal vessels
• Contrast-enhanced ultrasound
○ Enhancement of column of Bertin is identical
to normal renal cortex on all phases
CT Findings
• CECT
○ Similar enhancement as normal renal cortex on
corticomedullary and excretory phases
MR
Findings
• Similar signal intensity to renal cortex on
T1WI, T2WI, and contrast-enhanced sequences
PATHOLOGY
• Embryology: Incomplete resorption of polar
parenchyma of subkidneys that fuse to form normal kidney
○ Normal renal development: Superior and
inferior subkidneys corresponding to upper and lower calyces fuse, with upper pole of inferior subkidney
overlapping lower pole of superior subkidney
CLINICAL ISSUES
○ Asymptomatic, normal variant
• Diagnosis
○ Usually found incidentally on imaging
○ Most likely to simulate mass on sonography
○ Optimize ultrasound by focusing on lesion and
placing it in center of FOV
DIAGNOSTIC
CHECKLIST
Consider
• Normal variant, but can mimic solid tumor Image Interpretation Pearls
• Isoechoic to, and continuous with, renal
cortex
• Normal perfusion, no vascular distortion
• No mass on CECT or T1WI C+
• In duplication, bridging parenchyma separates
collecting systems; in column of Bertin, there is no bridging
Imaging gallery
 |
hypertrophied column of Bertin indenting the sinus fat in the mid kidney. Note its isoechogenicity relative to the cortex and the smooth external contour .
 |
hypertrophied column of Bertin which is isoechoic to renal cortex .
 |
| Enhanced MR of the previous patient (performed for another renal lesion, not shown) shows that the lesion has the same signal intensity as the renal cortex , compatible with a hypertrophied column of Bertin. |