Cobblestoning Sign

Cobblestoning Sign

Cobblestoning describes a characteristic ultrasonographic pattern of subcutaneous tissue in which multiple hypoechoic (fluid-filled) or hyperechoic (edematous) septations and fat lobules create a surface that resembles cobblestones. It is a nonspecific sign that indicates interstitial fluid, inflammation, or edema within the subcutaneous fat planes.

Sonographic Features

• Heterogeneous subcutaneous fat with multiple rounded hypoechoic areas separated by echogenic fibrous septa.
• Increased thickness of the subcutaneous layer compared with the contralateral side or normative values.
• Altered echotexture: loss of normal uniform fat echogenicity and increased fluid tracking along septa.
• Dynamic appearance may change with probe compression or patient position; Doppler may show increased vascularity if inflammation is present.

Common Sites

• Lower limbs — anterior/posterior shins and calves (cellulitis, lymphedema).
• Periorbital and facial subcutaneous tissues (inflammatory/edematous states).
• Abdominal wall and groin (postoperative edema, cellulitis).
• Breast and axillary fat in mastitis or post-procedural changes.

Sites of Cobblestoning

1. Subcutaneous Tissue
Cellulitis
Traumatic edema
Soft tissue infections

2. Skin & Breast
Mastitis
Breast cellulitis
Chronic dermatitis / panniculitis

3. Gastrointestinal Tract
Cobblestoning mucosa in Crohn’s disease (small bowel, colon)
Chronic inflammatory enteritis

4. Oropharynx & Upper Airway
Posterior pharyngeal wall (chronic postnasal drip, pharyngitis, allergic rhinitis)
Tonsillar region / lymphoid hypertrophy

5. Head & Neck Soft Tissues
Angioedema (facial / airway soft tissue)
Cervical cellulitis

6. Extremities
Lymphedema
Subcutaneous edema after trauma/infection

7. Other Soft Tissue Planes
Post-radiation tissue edema
Inflammatory panniculitis

Differential Diagnosis

• Cellulitis — cobblestoning with increased skin/subcutaneous thickness and hyperemia on color Doppler.
• Lymphedema — diffuse cobblestoning often bilateral and chronic, may show thickened septa without marked hyperemia.
• Necrotizing fasciitis — may show cobblestoning early, but look for fascial plane fluid, gas (hyperechoic foci with shadowing), and lack of perfusion.
• Traumatic fat stranding and contusion — history of injury and focal distribution.
• Postoperative/Postsurgical edema — localized cobblestoning adjacent to surgical sites or drains.

Cobblestoning — Related Pathologies

• Bacterial cellulitis — acute infection causing interstitial edema and hyperemia; responds to antibiotics.
• Lymphedema — chronic lymphatic insufficiency with persistent subcutaneous thickening and septal fibrosis.
• Venous stasis/edema — commonly in the lower legs with dependent pitting edema and skin changes.
• Inflammatory panniculitis (e.g., erythema nodosum) — may show nodular subcutaneous changes with variable vascularity.
• Early necrotizing soft-tissue infection — requires urgent assessment; cobblestoning alone is not diagnostic but should prompt evaluation for deeper fluid, gas, and systemic signs.

1. Subcutaneous Edema / Cellulitis

• In ultrasound of cellulitis, cobblestoning is a classical finding.
• Hypoechoic fluid (edema, pus) interspersed with hyperechoic fat lobules gives a cobblestone pattern.
• Helps differentiate cellulitis from a discrete abscess.

2. Allergic Reactions (Angioedema)

• Seen in skin and soft tissue swelling.
• Edematous hypoechoic areas between subcutaneous fat septae form cobblestoning.
• Often associated with airway/face swelling.

3. Inflammatory Bowel Disease (Crohn’s Disease)

• “Cobblestoning mucosa” is described in endoscopy of Crohn’s.
• Due to deep longitudinal and transverse ulcerations with edematous mucosa between them.

4. Lymphoid Hypertrophy in Oropharynx

• Seen on ultrasound or endoscopy of posterior pharyngeal wall.
• Cobblestoning indicates chronic postnasal drip, allergic rhinitis, or pharyngitis.

5. Chronic Lymphedema

• Skin thickening with subcutaneous septal edema may produce cobblestoning appearance on ultrasound/MRI.

6. Breast / Soft Tissue Infections

• Mastitis and breast cellulitis can show cobblestone pattern of subcutaneous edema.

7. Dermatological Disorders

• Chronic dermatitis or panniculitis may cause skin and subcutaneous tissue cobblestoning.

Clinical Pearls

• Compare with the contralateral side and correlate with clinical signs (erythema, warmth, pain, fever).
• Use compression and color Doppler: increased blood flow supports cellulitis; absence of flow with deep fluid collections raises concern for necrotizing infection.
• When in doubt, document and recommend clinical correlation or repeat imaging — ultrasound is excellent for superficial assessment but limited for deep fascial evaluation.

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Cobblestoning Sign — Bilingual MCQ Panel

Definition • Imaging features • Clinical relevance (English / हिन्दी)

Both / दोनों English हिन्दी

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