Vascular Malformation Sclerotherapy

Background and indications

Lymphatic malformations (LM), formerly called lymphangiomas, are congenital anomalies of the lymphatic system. They present as macrocystic (cavities > 1 cm, most favorable for treatment), microcystic (cavities < 1 cm), or mixed. They are common in the cervical region (cystic hygroma), axillary, mediastinal, and retroperitoneal areas.

Percutaneous sclerotherapy is the first-line treatment for symptomatic macrocystic LMs (pain, compression, superinfection, cosmetic concerns). It is less effective for pure microcystic forms.

Pre-procedure assessment

Assessment includes MRI (extension, macro vs microcystic character, anatomic relationships with critical structures — nerves, vessels, aerodigestive tract), Doppler ultrasound (low-flow confirmation, absence of arteriovenous component), and standard blood panel.

Procedure

Under general anesthesia (children) or sedation (adults), one or more needles are inserted into macrocysts under ultrasound guidance. Cyst contents (clear or chylous fluid) are aspirated. A sclerosing agent is injected: doxycycline (most used in children, 10 mg/mL), bleomycin (max 1 mg/kg), OK-432 (Picibanil), or ethanol (reserved for adults). Injected volume is adapted to cyst size. Multiple sessions (2-5) spaced 6-8 weeks apart are usually needed.

Results and scientific evidence

For macrocystic LMs, response rate (volume reduction > 50%) is 80-95% after multiple sessions. Macrocystic forms respond significantly better than microcystic or mixed types. OK-432 (Picibanil) showed 87% response rate for macrocystic forms (Acevedo et al., Journal of Vascular Surgery, 2008; DOI: 10.1016/j.jvs.2008.05.052). Doxycycline is the most used first-line agent in children with a good safety profile.

Risks and complications

Local swelling and inflammation (near-universal, resolving in 1-2 weeks), fever (20-30%, especially with OK-432), cyst superinfection (< 5%), nerve injury (1-3%, for cervical LMs near facial nerve or brachial plexus), respiratory distress from acute swelling (< 2%, for cervical LMs — close monitoring required).

Recovery

1-2 night hospitalization (especially for cervical LMs due to obstructive swelling risk). Control MRI at 3 months.

Practical information

The procedure is performed as a short inpatient stay. It is performed by an interventional radiologist specialized in vascular malformations, ideally at a pediatric reference center for children.