Subcapsular perirenal hematoma

A subcapsular perirenal hematoma is a form of perirenal hematoma where blood accumulates beneath the renal capsular margin.

Pathology

It can arise from a number of causes

• trauma, important in assessing renal trauma grading
• post procedural, e.g. extracorporeal shock-wave lithotripsy (ESWL) 
• spontaneous
• due to an underlying associated lesion
  • renal cell carcinoma
  • renal angiomyolipoma
  • renal abscess

Radiographic features

CT

Typically seen as crescentic hematoma peripherally encapsulating a portion of the kidney. The attenuation value depends on the age of the hemorrhage.

Differential diagnosis

On imaging consider

• perirenal abscess: different clinical context unless rarely when superinfection of a perirenal hematoma leads to an abscess