Guidelines and parameters: percutaneous sclerotherapy for the treatment of head and neck venous and lymphatic malformations

Vascular anomalies are classified broadly into vascular tumors and vascular malformations.1 Vascular malformations are further subdivided based on the histology of the lesion and whether the lesion is ‘high flow’ or ‘low flow’.1–3 The ‘low flow’ vascular anomalies are the focus of this article, and this category is broadly comprised of venous malformations (VM) and lymphatic malformations (LM). VM and LM are congenital anomalies thought to occur secondary to developmental errors in venous or lymphatic patterning, respectively.3–6 These lesions most commonly affect the head and neck, and have a prevalence of approximately 1%.3 ,5 ,7 Lesions involving the aerodigestive tract may result in airway obstruction, impaired food intake, and prevent normal speech. Similarly, lesions that involve the orbit may compromise visual acuity or ocular mobility. Vascular malformations may become quite large and demonstrate contiguous extension from the neck into the chest, pleura, cervical spine, or thoracic spine with associated pleural effusions and osteolysis. The vast majority of VM and LM are sporadic, although an increased prevalence of these anomalies has been described in multiple syndromes and with inherited gene mutations.8–13 It is important to recognize the categorization of LM into macrocystic or microcystic subtypes when contemplating treatment of these lesions. Macrocystic LM are comprised of larger cysts (≥2 cm in diameter) and respond well to percutaneous sclerotherapy and surgery with good to excellent outcomes in 76–95% of patients.3 ,8 ,14–17 By contrast, microcystic LM are comprised of innumerable small cysts (<2 cm in size) and tend to respond poorly to percutaneous sclerotherapy or surgery.3 ,8 ,18–20 Emerging data regarding the medical treatment of microcystic LM with sildenafil and the mTOR inhibitor sirolimus are promising, but these studies are still in an investigational stage.21 Effective treatment of superficial microcystic …