Approach to Vascular Anomalies in Children: A Guide for Primary Care Physicians

Dr Lynette Wee Wei Yi, Senior Consultant, Department of Dermatology, KK Women’s and Children’s Hospital

Vascular anomalies are relatively common in children and encompass a diverse group of vascular tumours and malformations with distinct clinical behaviours and management. This article outlines a practical approach to recognising common vascular anomalies, differentiating between lesion types, identifying red flags and knowing when specialist referral is warranted.

INTRODUCTION

Vascular anomalies result from the disordered development of blood vessels and represent common clinical problems in paediatric practice, affecting approximately 4.5% of children.^1,2 While some lesions spontaneously resolve, others cause significant complications affecting multiple organ systems.

Accurate diagnosis is crucial as different vascular anomalies require distinct management strategies. Up to 90% can be diagnosed clinically without imaging or biopsies, emphasising the importance of clinical recognition by primary care physicians.²

Early recognition and appropriate referral significantly impact outcomes and quality of life.² These complex conditions require coordinated care from dermatology, haematology/ oncology, interventional radiology and surgery working together to provide comprehensive evaluation, treatment and monitoring.^3,4

ISSVA CLASSIFICATION

The International Society for the Study of Vascular Anomalies (ISSVA) classification divides vascular anomalies into two major categories: vascular tumours and vascular malformations.¹ An overview of the ISSVA classification is shown in Table 1.

VASCULAR TUMOURS

Vascular tumours show excessive cell proliferation and grow out of proportion to the child’s growth. They include benign tumours (infantile haemangioma, congenital haemangioma), locally aggressive tumours (kaposiform haemangioendothelioma, tufted angioma) and, rarely, malignant tumours.

VASCULAR MALFORMATIONS

Vascular malformations consist of abnormally formed vessels with normal cell turnover.⁵ They are present at birth and grow proportionately with the child, although they may enlarge during puberty or after trauma.¹ Malformations are categorised by vessel type and flow:slow-flow (capillary, lymphatic, venous) or fast-flow (arteriovenous malformations and fistulas).^3,5 They can be simple (one vessel type) or combined (multiple vessel types), and some occur as part of syndromes affecting other organ systems.^2,6

GENETIC BASIS

Most vascular malformations result from somatic mutations occurring during foetal development - they are not inherited and occur sporadically.^4,7

Two main pathways are important for primary care physicians to understand.

PIK3CA pathway mutations cause the PIK3CA-related overgrowth spectrum (PROS), a group of disorders characterised by vascular malformations with overgrowth of fat, muscle or bone (Figure 5). These mutations are found in approximately 90% of lymphatic malformations and 30-50% of venous malformations. Discovery of these mutations has enabled targeted therapy with mTOR inhibitors like sirolimus.^1,7,8

RAS pathway mutations (“RASopathies”) are associated with arteriovenous malformations, capillary malformations and certain syndromes including capillary malformation arteriovenous malformation syndrome.⁸ Some conditions like hereditary haemorrhagic telangiectasia are inherited and may affect multiple family members. Genetic testing of affected tissue is increasingly important as targeted therapies become available.^1,4,7

DIAGNOSTIC APPROACH

Clinical assessment is the primary basis for diagnosis.²

• History should include timing of onset (present at birth versus postnatal), progression (rapid versus proportionate growth) and symptoms (pain, bleeding, functional impairment).
• Physical examination assesses colour (red, blue, flesh-coloured), consistency (soft, firm, compressible), temperature and the presence of thrill or bruit.

Imaging helps characterise lesions when diagnosis is uncertain. Ultrasound with Doppler differentiates high flow from low-flow lesions. MRI with angiography provides detailed anatomical information and identifies associated anomalies.

Laboratory tests may include complete blood count and coagulation studies to assess for complications.Tissue biopsy and genetic testing are reserved for uncertain diagnoses or when targeted therapy is considered.^4,7

TREATMENT OPTIONS

Treatment is individualised based on lesion type, location, symptoms and complications. Many lesions require observation only.

Medical therapy includes beta-blockers (propranolol, topical timolol) as first-line treatment for infantile haemangiomas requiring intervention, with high response rates when started early.^1,2

The mTOR inhibitor sirolimus effectively treats PIK3CA related conditions including complicated lymphatic and venous malformations, kaposiform haemangioendothelioma and overgrowth syndromes.^7,8

Corticosteroids and chemotherapy agents like vincristine are used for locally aggressive tumours.

Interventional radiology plays a central role. Sclerotherapy is the primary treatment for many venous and lymphatic malformations. Embolisation is essential for arteriovenous malformations and high-flow lesions. These minimally invasive techniques have become the mainstay of treatment with improved outcomes and decreased morbidity compared to surgery alone.³

Laser therapy treats specific lesions: pulsed dye laser for port-wine stains and CO2 laser for microcystic lymphatic malformations.^2,9

Surgery is now less commonly performed alone but remains important for localised lesions amenable to complete resection, for debulking in combination with other modalities and for managing complications.⁹ It is typically combined with other treatments rather than used as the sole approach.³

RED FLAGS FOR REFERRAL

Primary care physicians should refer to a specialised vascular anomalies clinic when high-risk features are present.

High-risk lesions

• Rapidly growing lesions that grow out of proportion to the child warrant urgent evaluation.
• Infantile haemangiomas in high-risk locations require early referral as treatment with propranolol is most effective when started early, ideally before 5 months of age. High-risk locations include the periorbital (risk of vision problems), nose/lips/genitals (ulceration, deformation), beard distribution (airway involvement), and segmental facial lesions >5 cm (PHACES syndrome with brain, heart and eye abnormalities). Segmental lumbosacral lesions may indicate spinal abnormalities. Multiple haemangiomas (≥5) require screening for liver involvement.²
• Warm, tender, indurated, violaceous lesions suggest kaposiform haemangioendothelioma, which can cause life-threatening Kasabach-Merritt phenomenon with severe thrombocytopenia and bleeding. This requires urgent referral.²

Symptoms warranting referral
Symptomatic lesions causing pain, recurrent swelling or infections, bleeding or discharge, or functional impairment affecting vision, breathing, mobility or feeding warrant specialist evaluation.^2,7

Associated systemic features
Systemic manifestations require urgent referral.

• Segmental port-wine stains over the trigeminal area raise concern for Sturge-Weber syndrome with brain involvement.
• Neurological deficits may indicate PHACES syndrome or spinal complications.
• Cardiac symptoms (tachypnoea, heart failure signs) can occur with large high-flow lesions.
• Bleeding diathesis with petechiae and thrombocytopenia suggests Kasabach-Merritt phenomenon requiring intensive care.
• Gastrointestinal or mucosal bleeding may indicate internal vascular malformations.

Syndromic features

Syndromic features that should prompt referral for comprehensive evaluation^2,6 include:

• Limb overgrowth or asymmetry
• Associated structural anomalies (eye abnormalities, spinal defects), or
• Family history of similar lesions or bleeding disorders

Diagnostic uncertainty
Diagnostic uncertainty, atypical appearance, lesions not responding to expected treatment or complex/extensive lesions benefit from specialist consultation.²

CONCLUSION

Recognising high-risk vascular anomalies and their complications is essential for primary care physicians. Initial assessment can be done based on history and physical examination. While many vascular anomalies can be managed conservatively, those with high-risk features require referral to a multidisciplinary team. Early recognition and timely referral significantly impact prognosis and quality of life for affected patients.^1,2,4

REFERENCES

1. International Society for the Study of Vascular Anomalies. ISSVA classification of vascular anomalies 2025. Retrieved on 20th May 2026 from https://www.issva.org/classification
2. Approach to Clinically Significant Vascular Anomalies in Children. Tanugroho RR, Wee LWY, Koh MJA, Chong JH. Singapore Medical Journal. 2023;64(12):714-720.doi:10.11622/smedj.2021209.
3. An overview of interventional radiology techniques for the diagnosis and management of vascular anomalies: Part 1. Scollan ME, Azimov N, Garzon MC, Tulin-SilverS. Pediatric Dermatology. 2023;40(2):242-249. doi:10.1111/pde.15246.
4. Clinical Approaches to the Diagnosis and Treatment of Vascular Anomalies. Gosain AK, Rai P, George E, Rodriguez GC. Plastic and Reconstructive Surgery.2026;157(6):923e-942e. doi:10.1097/PRS.0000000000012896.
5. ACR Appropriateness Criteria® Soft Tissue Vascular Anomalies: Vascular Malformations and Infantile Vascular Tumors (Non-Cns)-Child. Bardo DME, Gill AE, Iyer RS,et al. Journal of the American College of Radiology : JACR. 2024;21(6S):S310-S325. doi:10.1016/j.jacr.2024.02.030.

Dr Lynette Wee is a board-certified Paediatrician at KK Women’s and Children’s Hospital and went on to train in Paediatric Dermatology. She has a keen interest in atopic dermatitis, complex vascular anomalies, genetic skin disorders, histiocytic disorders and inpatient paediatric dermatology. She is also the treasurer of the Rare Skin Conditions Society (RSCS) Singapore and is passionate about promoting awareness of rare skin conditions and providing support for these patients who may require costly long-term medical care.

GP Appointment Hotline: 6294 4050.
Referral to KKH Vascular Anomalies Clinic: vascularanomalies@kkh.com.sg or centralappt@kkh.com.sg

The SingHealth Duke-NUS Vascular Centre brings together specialists from across SingHealth institutions to provide seamless and multidisciplinary care for vascular conditions.