Caesarean scar niche

Last revised by Karen Machang'a on 15 Oct 2023

The term caesarean scar niche (defect) refers to the presence of a hypoechoic area within the myometrium in the isthmus (lower uterine segment) with discontinuation of myometrium at the site of a previous caesarean section scar. A niche has been described as the indentation of myometrium of around 1-2 mm 1,4 due to tethering of the endometrium. 

They are encountered in various shapes such as:

  • semicircular: considered commonest 4
  • triangular: next commonest 4
  • droplet‐shaped
  • inclusion cysts

Due to tethering of the endometrium, blood accumulates in a niche and may serve as a source of dysfunctional uterine bleeding, accounting for spotting 2-12 days after the routine menstrual cycle 5.

See also

Cases and figures

  • Case 1
  • Case 2a: with blood collection- US
  • Case 2b: with blood collection- MRI
  • Case 3: incidental finding on lumbar spine MRI
  • Case 4
:

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