Definition/General
Introduction:
Colorectal hemangioma is a benign vascular tumor composed of proliferating endothelial cells forming vascular channels
It represents <1% of all colorectal tumors
Most commonly occurs in the rectosigmoid region
Shows excellent prognosis with complete excision.
Origin:
Arises from endothelial cells lining blood vessels
Can originate from submucosal vessels
May arise from deeper vascular plexuses
Shows benign proliferation of vascular elements
Demonstrates hamartomatous nature in some cases.
Classification:
Classified as capillary hemangioma (small vessels)
Cavernous hemangioma (large vessels)
Mixed type hemangioma
Epithelioid hemangioma (rare)
Pyogenic granuloma (lobular capillary hemangioma)
WHO classification: Benign vascular tumor.
Epidemiology:
Peak incidence in 5th-6th decades
No gender predilection
More common in rectosigmoid region (70%)
Rare entity in colorectum
Often asymptomatic
May present as incidental finding on colonoscopy.
Clinical Features
Presentation:
Rectal bleeding (most common symptom)
Asymptomatic polyp
Change in bowel habits
Abdominal pain (uncommon)
Iron deficiency anemia
Tenesmus in rectal location
Palpable mass on examination.
Symptoms:
Painless rectal bleeding (60-70% cases)
Hematochezia
Chronic blood loss leading to anemia
Mucus discharge
Feeling of incomplete evacuation
Rarely massive bleeding
Constitutional symptoms rare.
Risk Factors:
No specific risk factors identified
Congenital predisposition possible
Trauma may trigger growth
Hormonal changes (pregnancy)
Hereditary hemorrhagic telangiectasia (rare association)
Blue rubber bleb nevus syndrome.
Screening:
No specific screening required
Colonoscopy for symptomatic patients
CT angiography for large lesions
MRI for extent evaluation
Endoscopic ultrasound for submucosal lesions
Biopsy for histological confirmation.
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Gross Description
Appearance:
Well-circumscribed vascular mass
Red to blue coloration
Soft, compressible consistency
Sponge-like cut surface
Blood-filled spaces visible
Smooth surface if submucosal.
Characteristics:
Polypoid or sessile morphology
Hemorrhage may be present
Thrombosis in some vessels
Calcification (phleboliths) rare
Intact overlying mucosa
Well-demarcated from surrounding tissue.
Size Location:
Size ranges from 0.5-5 cm typically
Rectosigmoid region most common (70%)
Left-sided predominance
Cecum second most common
Submucosal location predominant
Intramural extension possible.
Multifocality:
Usually solitary (90% cases)
Multiple lesions in syndrome cases
Blue rubber bleb nevus syndrome - multiple GI hemangiomas
Hereditary hemorrhagic telangiectasia - multiple sites
Isolated colorectal involvement most common.
Microscopic Description
Histological Features:
Proliferation of endothelial cells forming vascular spaces
Capillary-type vessels or cavernous spaces
Single layer of endothelium
Basement membrane present
Supporting stroma minimal
No atypia in endothelial cells.
Cellular Characteristics:
Bland endothelial cells lining vascular spaces
Flattened nuclei
Minimal cytoplasm
No pleomorphism
Rare mitoses
Pericytes around larger vessels
Smooth muscle in vessel walls.
Architectural Patterns:
Capillary hemangioma: small, uniform vessels
Cavernous hemangioma: large, dilated spaces
Lobular architecture in some cases
Feeder vessels at periphery
Fibrous septa between vascular spaces
Thrombosis may organize.
Grading Criteria:
No grading system for benign hemangiomas
Cellularity assessment helps exclude angiosarcoma
Mitotic activity minimal (<1/10 HPF)
Nuclear atypia absent
Endothelial multilayering absent.
Immunohistochemistry
Positive Markers:
CD31 positive (endothelial marker)
CD34 positive
Factor VIII positive
ERG positive (nuclear)
FLI-1 positive (nuclear)
Vimentin positive.
Negative Markers:
Smooth muscle actin negative (except pericytes)
Desmin negative
Cytokeratins negative
S-100 negative
c-KIT negative
EMA negative.
Diagnostic Utility:
Confirms vascular nature
CD31/CD34 most reliable endothelial markers
ERG nuclear staining specific for endothelium
Rules out other tumors
Differentiates from GIST
Excludes epithelial tumors.
Molecular Subtypes:
No specific molecular subtypes
Ki-67 low proliferation index (<5%)
GLUT1 may be positive (infantile type)
D2-40 positive in lymphatic type
Prox1 in lymphatic endothelium.
Molecular/Genetic
Genetic Mutations:
No specific mutations identified consistently
Somatic mutations rare
PIK3CA mutations in some cases
AKT1 mutations rarely
Different from cutaneous hemangiomas genetically
Clonal vs reactive nature debated.
Molecular Markers:
VEGF expression variable
Angiopoietin-1/Tie-2 pathway involvement
bFGF expression in some cases
PDGF in supporting cells
Low proliferation markers
Apoptosis markers low.
Prognostic Significance:
Excellent prognosis with complete excision
No malignant potential
Rare recurrence after excision
Bleeding risk main concern
Large size increases bleeding risk
Complete excision curative.
Therapeutic Targets:
Complete surgical excision
Endoscopic resection for small lesions
Segmental resection for large lesions
Sclerotherapy for selected cases
Anti-angiogenic therapy not indicated
Surveillance after incomplete excision.
Differential Diagnosis
Similar Entities:
Angiosarcoma - malignant, atypical endothelial cells, high mitoses
Kaposi sarcoma - spindle cells, HHV-8 positive
Arteriovenous malformation - thick-walled vessels, no tumor
Pyogenic granuloma - lobular pattern, surface ulceration
Angiolipoma - mixed vascular and adipose elements.
Distinguishing Features:
Angiosarcoma: pleomorphic cells, multilayering, high Ki-67
Kaposi sarcoma: spindle morphology, slit-like spaces, HHV-8+
AVM: non-neoplastic, thick muscular walls
Pyogenic granuloma: surface lobular pattern, granulation tissue
Angiolipoma: mature fat admixed with vessels.
Diagnostic Challenges:
Small biopsy samples may be inadequate
Crush artifact in endoscopic biopsies
Distinguishing from AVM
Reactive vs neoplastic nature
Excluding angiosarcoma in cellular areas.
Rare Variants:
Epithelioid hemangioma - epithelioid endothelial cells
Spindle cell hemangioma - spindle cell areas
Microvenular hemangioma - small venular channels
Hobnail hemangioma - hobnail endothelium
Anastomosing hemangioma - anastomosing pattern.
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
Colorectal biopsy/resection containing a [size] cm vascular lesion
Diagnosis
Colorectal Hemangioma
Classification
Benign vascular tumor - [capillary/cavernous/mixed] type
Histological Features
Shows proliferation of bland endothelial cells forming vascular channels. No atypia or increased mitotic activity.
Size and Extent
Size: [X] cm, limited to [submucosa/muscularis propria]
Margins
Margins: [involved/uninvolved]
Immunohistochemistry
CD31: positive, CD34: positive, ERG: positive (nuclear), Ki-67: low
Special Studies
Immunohistochemistry confirms vascular differentiation
No molecular testing required
Endothelial markers positive
Final Diagnosis
Colorectal hemangioma, [capillary/cavernous] type