Apparent extra-hepatic invasion by metastatic tumours in the liver

Focal changes involving the liver capsule, subjacent tumour and contiguous structures are described on computed tomography (CT) in patients with metastatic tumours in the liver. These changes were correlated with the relevant resected liver tissue which had been perfused and sliced in planes comparable to the CT slices. The capsular changes represented 'umbilication', overlying necrotic and fibrosed tumour with contiguous structures, usually the diaphragm, perihepatic fat or omentum, fixed to the liver capsule by inflammatory or organising processes, but not invaded by tumour. Localised hypodense areas on CT in the region of the capsule do not represent extracapsular spread of tumour and therapy ought to be planned accordingly.