Angiomatosis

The pathology is of a soft tissue tumour, which appears derived from endothelial elements. The cases are classified as a developmental abnormality. Thinking on the origin of all angiomas is that they probably result from proliferation of residual collections of vascular precursors remaining after organogenesis. The group can be divided into those that have blood flow in them and those which don't. When there is blood flow, the mass of vessels is often venous and is often indicated by the presence of phleboliths. This category does not include arterio-venous malformations.

There is a group of tumours that contain cystic spaces. The lining may be lymph or blood vessel endothelium, but the tissue is derived from the same cells. Nomenclature is confused. Expression of the process can be limited to one focus or can be more widespread. Involvement of the pelvis is more common. The lungs may be involved and the process is a cause of chylous pleural effusions. Presentation can be anytime, but often is adolescence. Massive osteolysis or Gorham's disease can be included in this name. Usually a single bone is involved and replaced by cystic spaces, often without bone reaction. Involvement can begin with erosion of the margin of a bone.

One subset of cases of haemangioma is associated with limb overgrowth. This implies that the abnormal vessels contain moving blood, (often venous).