Intro & Classification - Vessel ID Parade
Congenital vascular anomalies (CVAs): localized defects in vascular morphogenesis. ISSVA classification is standard.
- ISSVA Categories:
- Vascular Tumors: Endothelial proliferation (e.g., Infantile Hemangioma). Often involute.
- Vascular Malformations: Morphogenesis errors. Present at birth, grow with child, do not involute.
- Simple: Capillary (CM), Venous (VM), Lymphatic (LM), Arteriovenous (AVM - high flow).
- Combined: e.g., Klippel-Trenaunay.
⭐ Vascular malformations are errors of morphogenesis, grow commensurately with the child, and do not spontaneously involute (unlike many infantile hemangiomas).
Low-Flow Malformations - Gentle Flow Issues
Congenital errors of vascular morphogenesis with slow blood flow.
| Type | Clinical Features | Syndromes | Histology |
|---|---|---|---|
| Capillary | Pink/red macules (port-wine stain/nevus flammeus), darken; no thrill. | Sturge-Weber (SWS), Klippel-Trenaunay (KTS) | Dilated dermal capillaries. |
| Venous | Soft, compressible, blue masses; swell with dependency; pain, thrombosis. | Klippel-Trenaunay, Blue Rubber Bleb (BRBNS) | Dilated, irregular venous channels; phleboliths. |
| Lymphatic | Macrocystic (cystic hygroma) or microcystic; clear fluid; infections. | Turner, Noonan, Gorham-Stout | Dilated lymphatic channels, flat endothelium. |
📌 SWS: Stain (Port-wine), Seizures, Sight (glaucoma).
⭐ Sturge-Weber syndrome (encephalotrigeminal angiomatosis) classically presents with a facial port-wine stain (nevus flammeus) in the V1/V2 trigeminal distribution, ipsilateral leptomeningeal angiomatosis, and glaucoma.
High-Flow Malformations - Wild Waterways
- Direct artery-to-vein shunts, bypassing capillaries; rapid flow.
- Often warm; may present as pulsatile mass.
- Types:
- Arteriovenous Malformations (AVMs): Nidus of dysplastic vessels.
- Arteriovenous Fistulas (AVFs): Direct artery-vein connection.
- Key Signs:
- Palpable thrill, audible bruit. 📌 (Nicoladoni-Branham sign: bradycardia on fistula compression).
- Skin: warm, red, ulceration, bleeding.
- Limb overgrowth.
- Risks:
- High-output heart failure (↑preload).
- Hemorrhage.
- Distal ischemia (steal phenomenon).
- Pain, neurological deficits (CNS AVMs).
- Dx: Doppler US, MRA/CTA, Angiography (gold standard).
- Rx: Embolization, surgery, radiosurgery.
⭐ A palpable thrill or audible bruit over a vascular lesion is highly suggestive of a high-flow arteriovenous malformation (AVM) due to direct shunting of blood.
Infantile & Congenital Hemangiomas - Berry Mark Tales
📌 IH: Grows then Goes; CH: Stays or Fades Fast
Key differences between these common benign vascular tumors:
| Feature | Infantile Hemangioma (IH) | Congenital Hemangioma (CH) |
|---|---|---|
| Onset | Postnatal (first few weeks), grows rapidly | At birth (fully formed), minimal postnatal growth |
| GLUT-1 | Positive (hallmark) | Negative |
| Natural History | Proliferate (6-12 mo) → Plateau → Involute (over years) | RICH: Rapid involution (by 12-18 mo); NICH: Persists/grows proportionally |
| Appearance | Bright red "strawberry" (superficial); can be deep/mixed | Often violaceous, telangiectatic, central pallor/halo; RICH/NICH types |
High‑Yield Points - ⚡ Biggest Takeaways
- Arteriovenous Malformations (AVMs): Direct artery-to-vein connections; high risk of cerebral hemorrhage.
- Capillary Malformations (Port-Wine Stains): Strongly linked to Sturge-Weber syndrome (facial stain, leptomeningeal angioma, glaucoma).
- Hereditary Hemorrhagic Telangiectasia (HHT/Osler-Weber-Rendu): Autosomal dominant; mucocutaneous telangiectasias, recurrent epistaxis, organ AVMs.
- Lymphatic Malformations (e.g., Cystic Hygroma): Often in neck/axilla; can cause airway obstruction.
- Klippel-Trenaunay Syndrome: Characterized by capillary malformation, venous varicosities, and bony/soft tissue hypertrophy.
- Developmental Venous Anomalies (DVAs): Most frequent intracranial vascular anomaly; usually asymptomatic and benign.
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