Haemorrhagic pulmonary metastases
Haemorrhagic pulmonary metastases are those which tend to be complicated by pulmonary haemorrhage within them, resulting in characeristic imaging appearances. Metastases of some tumour histologies are more likely to haemorrhage -- knowledge of this can help refine the differential diagnoses.
Haemorrhage is mostly thought to be due to fragility of neovascular tissue that leads to a rupture of the vessel.
Recognised types generally tend to have high vascularity within them and include 1-2
- angiosarcoma - metastatic angioscarcoma to the lungs
- choriocarcinoma - metastatic choriocarcinoma to the lungs
- renal cell carcinoma
If there is a peri-tumoural haemorrhage this may be seen as a nodule or mass which is surrounded by a halo of ground-glass opacity (CT halo sign) or an ill-defined fuzzed out margin.
For a suspected nodule or mass giving a CT halo sign - see differential for a CT halo sign
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