T1 weighted MRI scans vary from low to high intensity depending on the amount of adipose tissue present. T2 weighted MRI scans demonstrate lesions with high intensity due to the vascularity. On gross examination, hemangiomas are cystic, dark red cavities. The lesion is well demarcated and has trabecular thickening. Capillary and cavernous lesions are the most common in bone.
Capillary hemangiomas contain capillary size vessels lined by flattened endothelial cells.
Cavernous hemangiomas are often found in the calvaria and contain large dilated vessels with flattened endothelium. Arteriovenous hemangiomas are remnants of fetal capillary beds and venous hemangiomas contain small thick-walled venous vessels. Non-vascular components of hemangiomas include fat, smooth muscle, fibrous tissue, bone, hemosiderin and thrombus. Treatment of hemangioma is unnecessary unless the lesion is symptomatic. Lesions in the calvarium should be resected with a thin margin of normal bone.