Interventional Radiology · Vascular Anomalies · ISSVA 2025
ISSVA Classification of Vascular Anomalies (2025)
The 2025 ISSVA classification separates vascular anomalies into vascular tumours, vascular malformations and potentially unique vascular anomalies, with malformations further organised by flow characteristics and involved vascular channels.
Purpose
To provide standard terminology and a biologically based framework for diagnosing vascular anomalies and guiding imaging, genetic assessment and multidisciplinary management.
| Major category | Subdivision | Principal groups | Representative examples |
|---|---|---|---|
| Vascular tumours | Benign | Tumours with benign biological behaviour | Infantile haemangioma; congenital haemangioma; tufted angioma; pyogenic granuloma; spindle-cell haemangioma |
| Vascular tumours | Borderline | Locally aggressive or rarely metastasising tumours | Kaposiform haemangioendothelioma; retiform haemangioendothelioma; papillary intralymphatic angioendothelioma; pseudomyogenic haemangioendothelioma |
| Vascular tumours | Malignant | Malignant vascular neoplasms | Angiosarcoma; epithelioid haemangioendothelioma |
| Vascular malformations | Slow-flow: capillary | Capillary malformations | Nevus simplex; port-wine capillary malformation; reticulate or telangiectatic capillary malformation; cutis marmorata telangiectatica congenita |
| Vascular malformations | Slow-flow: lymphatic | Isolated lymphatic malformation; complex lymphatic anomaly; lymphoedema | Macrocystic, microcystic or mixed lymphatic malformation; generalised lymphatic anomaly; kaposiform lymphangiomatosis; Gorham–Stout disease; central conducting lymphatic anomaly |
| Vascular malformations | Slow-flow: venous | Isolated, multifocal or syndromic venous malformations | Venous malformation; verrucous venous malformation; fibro-adipose vascular anomaly; glomuvenous malformation; blue rubber bleb naevus syndrome |
| Vascular malformations | Slow-flow: combined | Malformations involving two or more vascular channels | Capillary-lymphatic-venous malformation; lymphatic-venous malformation; capillary-lymphatic malformation; capillary-venous malformation |
| Vascular malformations | Fast-flow | Isolated, multifocal or syndromic fast-flow malformations | Arteriovenous malformation; congenital arteriovenous fistula; capillary malformation–arteriovenous malformation syndrome; hereditary haemorrhagic telangiectasia; Parkes–Weber syndrome |
| Vascular malformations | Developmental anomalies of named vessels | Abnormal origin, course, number, length, diameter, valves or persistence of named vessels | Developmental anomalies involving the aorta, vena cava, vein of Galen or other named vessels |
| Potentially unique vascular anomaly | PUVA | Lesions not yet confidently assigned to vascular tumour or vascular malformation | A provisional category pending clearer biological and genetic characterisation |
How to use it
- The first diagnostic distinction is between a vascular tumour and a vascular malformation; these terms are not interchangeable.
- Vascular tumours are classified by biological behaviour as benign, borderline or malignant.
- Vascular malformations are organised into slow-flow, fast-flow and developmental anomalies of named vessels.
- Slow-flow malformations are further classified by the predominant vascular channel as capillary, lymphatic, venous or combined.
- ISSVA terminology integrates phenotype, imaging, pathology and increasingly genotype; associated syndromes should be stated when recognised.
Common mistake
Do not use haemangioma as a generic label for every vascular anomaly. A venous malformation, lymphatic malformation or arteriovenous malformation is not a haemangioma.
Exam pearl
In a viva, classify the lesion in sequence: vascular tumour versus vascular malformation; if a malformation, slow-flow versus fast-flow versus named-vessel anomaly; then specify the involved vascular channel and any associated syndrome.
Viva questions
- What are the major categories in the 2025 ISSVA classification?
- Vascular anomalies are divided into vascular tumours, vascular malformations and potentially unique vascular anomalies, termed PUVA.
- What is the fundamental distinction between a vascular tumour and a vascular malformation?
- A vascular tumour represents a proliferative vascular neoplasm, whereas a vascular malformation is a structural developmental abnormality of vascular channels.
- How are vascular tumours classified by ISSVA?
- They are classified according to biological behaviour as benign, borderline or malignant.
- How are vascular malformations broadly classified according to flow?
- They are classified as slow-flow malformations, fast-flow malformations or developmental anomalies of named vessels.
- What are the principal slow-flow vascular malformation groups?
- The principal groups are capillary, lymphatic, venous and combined vascular malformations.
- What are the main fast-flow vascular malformations?
- The principal fast-flow lesions are arteriovenous malformations and congenital arteriovenous fistulas, occurring as isolated, multifocal or syndromic abnormalities.
- What does PUVA mean in the 2025 ISSVA classification?
- PUVA means potentially unique vascular anomaly. It is a provisional category for lesions that cannot yet be confidently assigned to either vascular tumours or vascular malformations.
- What is the commonest terminology error when describing vascular anomalies?
- The common error is calling every vascular lesion a haemangioma. Venous, lymphatic and arteriovenous malformations are distinct malformations and should be named accordingly.