venerdì 4 dicembre 2009
Lymphangioma with components of hemangioma
Multilobular, infiltrative mass posterior to the lower cervical/upper thoracic spine, which is soft tissue density on CT and on MR is T1 iso intense to muscle, T2 hyper intense, homogeneously enhances, and shows evidence of flow voids. There is also enhancement of the adjacent spinous process.
Diagnosis: Lymphangioma with components of hemangioma
Endothelial malformations are currently divided into hemangiomas and vascular malformations.
Previously these lesions were categorized and named according to the channel size and contained fluid: i.e. capillary, strawberry and cavernous hemangiomas for blood containing lesions; and lymphangiomas or cystic hygromas for lymph containing lesions.
Vascular malformations are not true neoplasms and they are subdivided into high-flow and low-flow groups.
High-flow vascular malformations have an arterial component and include both arteriovenous malformations and arteriovenous fistulas.
Low–flow vascular malformations include lymphangiomas and venous malformations.
Hemangiomas are true, benign, neoplasms of the endothelium, and represent the most common tumor of childhood.
Hemangiomas are characterized by their absence or subtlety at birth, followed by a period of rapid proliferation, and then eventual involution.
MRI and ultrasound are the main modalities used for imaging hemangiomas and vascular malformations.
Goals of imaging of hemangiomas and vascular malformations are
- lesion characterization
- anatomic location/extent
Hemangiomas are usually isointense on T1, hyper intense on T2, and show diffuse enhancement.
Low flow vascular malformations:
- Venous malformations are dilated, "serpentine", lesions, which are hyper intense on T2 and intermediate signal on T1, and may have slow contrast enhancement of the vessel channels. Low signal phleboliths may be seen.
- Lymphangiomas tend to "infiltrate" the adjacent anatomic structures, and contain variably sized cystic spaces which are variable on T1 (due to variable protein content), hyper intense on T2 and do not demonstrate enhancement of the central cystic spaces.
- High-flow vascular malformations are characterized by flow voids suggestive of rapid blood flow.
Treatment of hemangiomas is usually conservative.
Treatment of low flow vascular malformations is currently percutaneous sclerosis.
Treatment of high flow vascular malformations is arterial embolization.