Table 2. Classification systems with outcomes (8,14,18,19,26,36-38).

Grading scheme	Modality	Category	Anatomic features and hallmarks	Treatment	Implications for treatment
Goyal et al.	MRI based	Grade 1	Well defined, ≤5 cm diameter	Sclerotherapy (as monotherapy)	71% excellent results, 29% good results, 0% poor results
		Grade 2A	Well defined, >5 cm		22% excellent results, 44% good results, 33% poor results
		Grade 2B	Ill defined, ≤5 cm diameter		26% excellent results, 15% good results, 60% poor results
		Grade 3	Ill defined, >5 cm		0% excellent results, 43% good results, 57% poor results
Fayad et al.	MRI based	Extent	Focal, multifocal, or diffuse	Sclerotherapy	Multifocal treatments and multiple sessions are required
		Tissue layer involvement	Skin/subcutaneous/muscle/tendon/bony cortex/marrow		Risk of skin or nerve injury is considered; muscular involvement; risk of contracture; bone or marrow involvement; risk of fracture
		Connection	Deep venous system		Increased risk of deep venous thrombosis
Dubois	DPP based	Cavitary	Cavities with late venous drainage without abnormal veins	Sclerotherapy	Improved results
		Spongy	Small, ‘honeycomb’ cavities and venous drainage		Difficult to treat, particularly when the VM is intramuscular
		Dysmorphic	Rapid opacification of dysmorphic veins		Improved results, however recurrence is likely
Dubois/Puig	DPP based	Type I	Isolated, well circumscribed without visible venous drainage	Sclerotherapy	Highest rate of cure or satisfactory result, 92.3% complication-free predictive value
		Type II	Malformation draining into normal veins		High rate of cure or satisfactory result, 93.8% complication-free predictive value
		Type III	Malformation draining into ectatic dysplastic veins		50% exclusion rate, higher risk of complications
		Type IV	Venous ectasia		60% exclusion rate & higher risk of complications
Berenguer et al.	Direct contrast venogram	Lobulated	Rounded clusters of vascular spaces	Sclerotherapy (multiple therapy sessions, 1–10)	27% in all three categories rated outcome as near normal, 38% reported marked improvement, 13% reported slight improvement, and 4% reported no change
		Varicose	Irregular dilated channels		No significant difference in outcome could be shown between categories
		Combined	Combination of the above
Boston Children’s	Based on imaging and clinical features	Spongiform	Large sponge-like singular lesion	–	Most common type
		Phlebectatic	Large diameter combined vascular malformation		Increased risk of deep vein thrombosis and pulmonary embolism
		Aneurysmatic	Involves large veins such as inferior vena cava		Increased risk of deep vein thrombosis and pulmonary embolism
		Reticular	Small veins, spider-like appearance, combined vascular syndromes		50% have spontaneous Tie-2 mutations (unlike the autosomal dominant inheritance pattern found in familial mucocutaneous VMs)

VM, venous malformation.