Hip MRI/[Case]

The “Don’t Touch” Lesion: Synovial Herniation Pits Explained

MSK MRI 2025. 3. 1. 00:45

https://youtu.be/PqHvy3xzuVY

โœจ Join the channel to enjoy the benefits!
๐Ÿš€ https://www.youtube.com/channel/UC4bw7o0l2rhxn1GJZGDmT9w/join

https://youtube.com/shorts/4uXE8sluDX4

๐Ÿ“Œ Synovial Herniation Pit

 

โœ… Definition

Synovial herniation pits, also known as Pitt pits, are common and usually incidental imaging findings, often described as fibrocystic changes at the anterosuperior femoral neck.

 

โœ… Epidemiology

  • Found in ~5% (range: 4-12%) of normal adults on X-ray.

 

โœ… Associations

  • Linked to cam morphology femoroacetabular impingement (FAI), occurring in 5-33% of cases.
  • However, the causal relationship between FAI and synovial herniation pits remains unproven.

 

โœ… Pathology

  • The exact cause is debated.
  • Represents a herniation of synovium or soft tissue into bone through a cortical defect.
  • Commonly occurs at the anterosuperior femoral neck, but also reported in the anteroinferior region.
  • Size: Typically 5 mm (range: 1-15 mm).
  • More often unilateral than bilateral.

 

โœ… Plain Radiograph / CT

  • Appears as oval, round, or "8-shaped" lucencies with sclerotic margins.
  • CT may reveal an overlying cortical defect.

โœ… MRI

  • Well-defined lesion with low peripheral signal.
  • Central low T1 and high T2 signal, sometimes heterogeneous.
  • Some lesions contain intralesional fat.
  • Adjacent bone marrow edema is rare.

 

โœ… Treatment & Prognosis

  • Incidental finding with no clinical significance.
  • Considered a “don’t touch” lesion in radiology.
  • May enlarge over time but generally requires no treatment.

 

#SynovialHerniationPit, #PittPit, #FemoralNeck, #FAI, #HipRadiology, #MSKRadiology, #BoneLesion, #HipMRI, #SkeletalImaging, #RadiologyEducation

"Visualizing MSK Radiology: A Practical Guide to Radiology Mastery"

© 2022 MSK MRI Jee Eun Lee All Rights Reserved.

No unauthorized reproduction, redistribution, or use for AI training.