Fibrocystic Disease in the Popliteal Artery: Incidence and Biopsy Techniques

Advanced Vascular Surgery Presentation

Medical Presentation Professor Atef Allam

1. Incidence in the Popliteal Artery

Rare but documented:

The popliteal artery is less commonly affected compared to renal, aortic, or carotid arteries.

Estimated frequency:

  • <5% of FCDA cases involve the popliteal artery.
  • More often seen in diffuse systemic forms of the disease.

Clinical implications:

  • Stenosis → Claudication, chronic limb ischemia.
  • Aneurysm formation → Risk of rupture or distal embolism.
  • Mimics atherosclerosis or popliteal entrapment syndrome.

2. Biopsy Techniques for Histopathology

Since FCDA is a medial pathology, obtaining a full-thickness arterial biopsy is ideal but challenging.

A. Open Surgical Biopsy (Gold Standard)

Procedure:

  • Exposure: Popliteal artery accessed via medial/lateral approach.
  • Resection: A small segment (5–10 mm) is excised.
  • Reconstruction: Primary anastomosis or patch angioplasty.

Advantages:

  • Provides full-thickness specimen (intima, media, adventitia).
  • Allows simultaneous repair if aneurysm/stenosis is present.

Disadvantages:

Invasive, risk of hematoma, nerve injury, or thrombosis.

B. Endovascular Biopsy (Experimental)

Technique:

  • Directional atherectomy catheter (e.g., SilverHawk™) retrieves tissue.
  • Intravascular ultrasound (IVUS)-guided to target abnormal segments.

Limitations:

  • Small sample size (may miss cystic medial degeneration).
  • Fragmented specimens → harder to interpret.

C. Intraoperative Frozen Section (If Urgent)

  • Used when surgical decisions (e.g., bypass vs. repair) depend on histology.
  • Pitfall: Mucoid cysts may be missed on frozen analysis.

3. Histopathological Confirmation

Key features:

  • Cystic spaces in media (Alcian blue + for mucopolysaccharides).
  • Elastic fiber fragmentation (Verhoeff-van Gieson stain).
  • Absence of inflammation (vs. vasculitis) or lipid plaques (vs. atherosclerosis).

4. Clinical Considerations

Biopsy only if:

  • Diagnosis uncertain after imaging (CTA/MRI).
  • Atypical presentation (young patient without atherosclerosis).

Avoid biopsy if:

  • High rupture risk (large aneurysm).
  • Severe calcification (increased surgical risk).

5. Key Takeaways

  • Popliteal involvement is rare (<5%) but can cause limb ischemia or aneurysms.
  • Open biopsy is preferred for definitive diagnosis.
  • Endovascular biopsy is emerging but has limitations.
  • Histology must differentiate FCDA from atherosclerosis, vasculitis, or FMD.