Definition/General
Introduction:
Small intestinal hemangioma is a benign vascular tumor composed of proliferating endothelial cells and blood vessels
It represents rare benign tumors of the small bowel
It can be capillary, cavernous, or mixed type
It may cause GI bleeding and intestinal obstruction.
Origin:
Arises from endothelial cells of blood vessels
Results from abnormal vascular proliferation
May be congenital or acquired
Hamartomatous rather than true neoplasm
Associated with vascular malformations.
Classification:
Capillary hemangioma: small vessels
Cavernous hemangioma: large vascular spaces
Mixed type: both components
Arteriovenous malformation (related lesion)
Based on size: small (<2 cm), large (>2 cm).
Epidemiology:
Very rare tumors (<1% of small bowel tumors)
Equal gender distribution
Any age group affected
Jejunum most common location
Associated with hereditary syndromes (rare).
Clinical Features
Presentation:
GI bleeding (most common, 80% cases)
Iron deficiency anemia
Abdominal pain
Small bowel obstruction
Intussusception
Palpable mass (large lesions).
Symptoms:
Chronic GI bleeding (occult or overt)
Melena or hematochezia
Fatigue and weakness (anemia)
Crampy abdominal pain
Intestinal obstruction symptoms
Early satiety.
Risk Factors:
Hereditary hemorrhagic telangiectasia
Blue rubber bleb nevus syndrome
Klippel-Trenaunay syndrome
Maffucci syndrome
Family history of vascular malformations.
Screening:
Upper and lower endoscopy
Capsule endoscopy
CT angiography
Mesenteric angiography
Double-balloon enteroscopy
Technetium-99m RBC scan (bleeding).
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Gross Description
Appearance:
Red to purple masses
Soft, compressible consistency
Lobulated surface
Hemorrhagic appearance
Thrombosis may be present
Variable size (0.5-10 cm).
Characteristics:
Well-circumscribed lesions
Spongy consistency
Easily compressed
Hemorrhage and thrombosis common
Surface ulceration possible
Multiple lesions in syndromes.
Size Location:
Jejunum (most common, 50%)
Ileum (30%)
Duodenum (20%)
Size range: 0.5-10 cm
Submucosal location predominant
May extend transmurally.
Multifocality:
Usually solitary (sporadic cases)
Multiple lesions in hereditary syndromes
Throughout GI tract in some syndromes
Associated cutaneous lesions.
Microscopic Description
Histological Features:
Proliferating blood vessels of varying sizes
Endothelial-lined spaces containing red blood cells
Capillary or cavernous pattern
Thrombosis and organization
Inflammatory infiltrate.
Cellular Characteristics:
Benign endothelial cells lining vascular spaces
Flat endothelium without atypia
Pericytes around vessels
Red blood cells within lumina
Inflammatory cells: lymphocytes, histiocytes.
Architectural Patterns:
Capillary type: small vessels with narrow lumina
Cavernous type: large, dilated vascular spaces
Lobular arrangement
Fibrous septa between lobules
Thrombosis and calcification.
Grading Criteria:
No grading system (benign lesions)
Vessel size: capillary vs cavernous
Cellularity: low to moderate
Mitotic activity: absent to minimal
Endothelial atypia: absent.
Immunohistochemistry
Positive Markers:
CD31 (endothelial marker, positive)
CD34 (endothelial cells)
Factor VIII (von Willebrand factor)
ERG (endothelial transcription factor)
FLI-1 (endothelial marker).
Negative Markers:
CD117 (excludes GIST)
Desmin (excludes smooth muscle tumor)
S-100 (excludes nerve sheath tumor)
Cytokeratins (excludes carcinoma)
GLUT1 (excludes infantile hemangioma).
Diagnostic Utility:
Confirms endothelial nature of lining cells
Demonstrates vascular differentiation
Excludes other mesenchymal tumors
Distinguishes from angiosarcoma (no atypia)
Essential for diagnosis.
Molecular Subtypes:
Capillary hemangioma: small vessel pattern
Cavernous hemangioma: large vessel spaces
Arteriovenous malformation: mixed vessel types.
Molecular/Genetic
Genetic Mutations:
ACVRL1 mutations (hereditary hemorrhagic telangiectasia)
ENG mutations (HHT type 1)
SMAD4 mutations (HHT-JPS overlap)
TEK mutations (venous malformations)
GLA mutations (rare).
Molecular Markers:
VEGF expression
Angiopoietin signaling
TIE2 receptor
Notch pathway
Endothelial growth factors.
Prognostic Significance:
Excellent prognosis if completely excised
Bleeding risk: depends on size and location
Recurrence: rare with complete excision
Syndromic cases: multiple lesions, ongoing surveillance needed.
Therapeutic Targets:
Surgical excision
Endoscopic therapy: laser, sclerotherapy
Interventional radiology: embolization
Anti-angiogenic therapy (experimental)
Supportive care for bleeding.
Differential Diagnosis
Similar Entities:
Angiosarcoma
Kaposi sarcoma
Arteriovenous malformation
Glomus tumor
Hemangioendothelioma
Angiomatous polyp.
Distinguishing Features:
Hemangioma: benign endothelium, no atypia, low cellularity
Angiosarcoma: atypical endothelium, high cellularity, mitoses
Kaposi: HHV8+, spindle cells
AVM: thick-walled vessels
Glomus: SMA+ smooth muscle cells.
Diagnostic Challenges:
Distinguishing from angiosarcoma (atypia assessment)
Recognizing thrombosed hemangioma
Identifying syndromic associations
Correlation with imaging findings
Adequate tissue sampling.
Rare Variants:
Epithelioid hemangioma
Pyogenic granuloma
Intramuscular hemangioma
Microvenular hemangioma
Anastomosing hemangioma.
Sample Pathology Report
Template Format
Sample Pathology Report
Complete Report: This is an example of how the final pathology report should be structured for this condition.
Specimen Information
Small bowel segment with vascular lesion, [size] cm
Diagnosis
[Capillary/Cavernous] hemangioma of small intestine
Histological Features
Benign vascular tumor with proliferating blood vessels lined by normal endothelium
Vascular Pattern
[Capillary/Cavernous/Mixed] pattern with [description of vessels]
Endothelial Features
Benign endothelial cells without atypia or mitotic activity
Size and Location
Lesion size: [X] cm, location: [submucosal/intramural]
Margins
Excision margins: [complete/incomplete]
Special Studies
CD31: positive, CD34: positive, Ki-67: low proliferation index
Consider genetic evaluation if multiple lesions or family history
[other study]: [result]
Recommendations
Clinical correlation, surveillance for additional lesions if syndromic
Final Diagnosis
Small intestinal [capillary/cavernous] hemangioma, [size] cm, benign