Hemangioma (liver)

Commonest benign hepatic tumor
4-20% post-mortem prevalence
Vascular channels of varying size, lined with endothelium, has intervening fibrous tissue
Asymptomatic incidental findings
Lesions 2-4 cm in size show typical imaging findings

US: well defined, lobular, homogeneous, increased echo reflectivity. No doppler flow due to slow flow
MRI: most sensitive and specific. Extended ECHO time (120 to 160 ms) T2w SE sequences shows lesions to be homogeneously bright, almost fluid signal equivalent. Malignant lesions do not have increasing intensity in T2 at longer TE. Arterial phase shows rapidly enhancing vessels in periphery. Over time, lesion fills in centrally to become iso to slightly hyper intense than liver parenchyma
CT: well defined lobulation lesion with attenuation similar to blood in plain study. Pattern of enhancement similar to MRI
Liver sulphur colloid: photopenic lesions
Tc 99 m blood pool studies: increase in uptake

Lesions <1.5 cm in size difficult to characterize, do not show typical enhancement pattern. Often enhances rapidly and mimics other arterial enhancing lesions
Larger lesions can have central area of fibrosis that does not enhance until in delayed scans
Lesions when in doubt should be core biopsied. Core biopsy of hemangioma is safe unlike previously thought