KEY FACTS
Terminology
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Definition
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Defect or line representing incomplete embryologic fusion of 2 primary renal lobes: Upper and lower poles of kidney
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Synonyms
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Junctional parenchymal defect
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Interrenuncular septum
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Imaging
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Characteristic location at anterosuperior aspect of kidney, upper to middle 1/3 of kidney
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Wedge-shaped hyperechoic defect or echogenic line
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Variable size of defect
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No associated loss of parenchyma
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More commonly seen on right
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Overlays column of Bertin
Top Differential Diagnoses
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Scar
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Fetal lobulation
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Angiomyolipoma
Pathology
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Layer of connective tissue trapped from fusion of 2 metanephric elements in formation of kidney
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Deep diagonal groove extending from anterior surface of upper pole of kidney into hilum
Clinical Issues
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Normal variant
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No clinical sequelae
Scanning Tips
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Absence of parenchymal loss useful to differentiate it from cortical scar
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Increased echogenicity on ultrasound; no disturbance of vessels
as a thin echogenic line communicating with the renal sinus.
