Kaposiform Haemangioendothelioma and Tufted Angioma

What are kaposiform haemangioendothelioma & tufted angioma?
Kaposiform haemangioendothelioma (KHE) and tufted angioma (TA) are rare benign tumours of blood and lymphatic vessels. Although non-cancerous, they, in particular KHE, can grow fast and quite extensively into surrounding tissue in the affected area.

How does kaposiform haemangioendothelioma & tufted angioma present?
KKHE presents as a firm, deep nodule or swelling that has a bruise-like or purplish discoloration. It appears most commonly during the newborn period or within the first 2 years of life. It can grow or expand rapidly, especially during infancy.

TA presents as reddish nodules, swellings or patches that can grow over months. Most develop within the first year of life.

When lesions of KHE or TA become hard and firm, it may mean that there is blood trapping within the lesion, leading to Kasabach-Merritt syndrome.

Kaposiform haemangioendothelioma	Tufted angioma

What is the Kasabach-Merritt syndrome?
Kasabach-Merritt syndrome or KMS is the most serious complication of KHE and TA and occurs when blood cells (platelets) and proteins (clotting factors) responsible for blood clotting are trapped within a blood vessel tumour, leading to an increased risk of bleeding. It is most often caused by a growing KHE.

Infants with KMS present with swelling of the blood vessel tumour, associated with features of bleeding, including bruises, nose bleeds (epistaxis), blood in the urine (haematuria) or blood in the stools (haematochezia).

How are these conditions diagnosed?
KHE, TA and KMS are diagnosed by a combination of clinical history, physical examination and tests including blood tests, ultrasound, magnetic resonance imaging (MRI) and tissue biopsies.

KMS can be confirmed by blood tests including full blood count and clotting profile.

Ultrasound:

• Non-invasive, painless test to aid in the diagnosis of KHE and TA
• Can be performed either in the clinic or at the diagnostic imaging centre. A probe is placed on the skin over the site of the suspected KHE or TA.
• Duration: 10 to 30 minutes depending on the size and site of the lesion; will require some cooperation from the patient.

MRI:

• Provides more detail than ultrasound and can objectively demonstrate the size and extent of the lesion.
• Does not involve radiation.
• Duration: 45 to 60 minutes, sometimes longer, in a noisy environment. The patient needs to stay still, thus requiring general anaesthesia (GA) for infants and younger children who are unable to cooperate. GA is administered by our team of paediatric anaesthetists.

Tissue biopsies:

• May be required for the diagnosis of KHE and TA.
• If required, this involves cutting the skin and removing a small piece of tissue to look under the microscope.
• May be done under local anaesthetic if the child is cooperative. Otherwise, it can also be performed with sedation in the ward or with GA in the operating theatre.

How are these conditions treated?
Treatment of KHE, TA and KMS require multi-disciplinary management by a vascular anomalies team. Decision to treat depends on several factors, including the size and location of the tumour, whether KMS is present, and the severity of symptoms.

Not all KHE and TA require treatment. Small lesions without complications may be monitored without intervention.

Treatment options include infusion of blood products to stop or prevent bleeding, and systemic medications to shrink it, including corticosteroids (e.g. prednisolone), sirolimus or certain chemotherapy drugs like Vincristine.

Transarterial embolisation is a procedure where blood vessels feeding the tumour are blocked. This procedure is performed by our interventional radiologists and can be used in combination with sirolimus therapy for faster resolution of KMS.

If the tumour is small and accessible, surgery may be done.

Many patients, especially those with more complications, require multimodality treatment. The various treatment options will be discussed with the patient and caregiver at the Multidisciplinary Vascular Anomalies Clinic.

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