In a patient presenting with a large inferior mesenteric venous varix, is Portal Vein (PV) thrombosis or Hereditary Hemorrhagic Telangiectasia (HHT) more likely?

Portal Vein Thrombosis is Far More Likely Than HHT

In a patient with a large inferior mesenteric venous varix, portal vein (PV) thrombosis or splenic vein thrombosis causing portal hypertension is overwhelmingly more likely than hereditary hemorrhagic telangiectasia (HHT). 1

Why Portal Vein Pathology is the Primary Consideration

Established Pathophysiology of Inferior Mesenteric Varices

• Splenic vein thrombosis from pancreatic pathology is a well-recognized cause of isolated left-sided portal hypertension that forces blood through inferior mesenteric collaterals, creating varices 1

• Portal vein occlusion forces development of extensive portosystemic collaterals, with inferior mesenteric varices serving as alternative drainage pathways 1

• Cirrhotic portal hypertension with patent portal veins commonly produces inferior mesenteric varices as part of the portosystemic collateral network 2, 1

Clinical Context Strongly Favors Portal Venous Disease

The presence of an inferior mesenteric varix indicates established portosystemic collateral flow, which occurs in three specific scenarios 1:

1. Portal hypertension with patent portal vein (cirrhosis being most common)
2. Splenic vein thrombosis causing sinistral (left-sided) portal hypertension
3. Portal vein thrombosis with cavernous transformation

All three conditions have well-documented associations with inferior mesenteric varices 2, 1.

Why HHT is Extremely Unlikely

Rarity of Portal Venous System Involvement

• HHT rarely involves the portal venous system to cause serious clinical complications 3

• HHT has an incidence of approximately 1 in 5,000 in the general population, but portal venous involvement is exceptionally rare even among HHT patients 3, 4

• The typical HHT manifestations are arteriovenous malformations (AVMs) in the lungs, brain, liver, and gastrointestinal tract—not venous varices 4

Different Vascular Pathology

• HHT creates arteriovenous fistulas and malformations (direct artery-to-vein connections bypassing capillaries), not venous varices from portal hypertension 3, 4

• A large inferior mesenteric venous varix represents collateral venous drainage from elevated portal pressure, which is fundamentally different from the arteriovenous shunting seen in HHT 1

• The single case report of HHT involving mesenteric vessels described superior mesenteric arteriovenous fistulas, not inferior mesenteric venous varices, and the patient died from intestinal necrosis—highlighting how atypical and severe this presentation is 3

Critical Diagnostic Algorithm

The American College of Radiology mandates that you obtain cross-sectional imaging (portal venous phase CT or MRI) to distinguish between 1, 5:

1. Portal hypertension with patent portal vein
2. Splenic vein occlusion (sinistral portal hypertension)
3. Portal vein thrombosis with cavernous transformation

Each requires fundamentally different treatment approaches 1, 5:

• Splenic vein occlusion: Splenectomy or partial splenic embolization (100% success rate) 5
• Portal vein thrombosis: Portal vein recanalization plus TIPS (98% technical success) 5
• Patent portal vein with portal hypertension: BRTO if gastrorenal shunt present, or TIPS for significant portal hypertension 5

Common Pitfall to Avoid

Never assume inferior mesenteric varices indicate only cirrhosis—always obtain imaging to identify the specific vascular pathology, as splenic vein thrombosis from pancreatitis can occur in non-cirrhotic patients and requires completely different management than cirrhotic portal hypertension 1, 5.

The presence of other HHT stigmata (recurrent epistaxis, mucocutaneous telangiectasias, family history, pulmonary or cerebral AVMs) would be necessary to even consider HHT in this context 4. Without these features, portal venous pathology is the diagnosis until proven otherwise.