Specific Imaging Findings

Tumoral intracranial hemorrhages can be difficult to distinguish from more common spontaneous hemorrhages, primarily due to hypertension, amyloid angiopathy, vascular malformations, or venous thrombosis. Features of an acute hemorrhage which favor the presence of an underlying tumor include a complex and heterogeneous appearance, the presence of a nonhemorrhagic mass within or adjacent to the hematoma, multiplicity (suggesting hemorrhagic metastases), and areas of nodular post-contrast enhancement. On CT neoplastic hemorrhages will be heterogeneously hyperdense acutely, and will occasionally demonstrate fluid levels if hemorrhage extends into a cystic portion of a tumor (fluid levels may notably be also seen with amyloid bleeds). The presence of enhancement within or adjacent to a hemorrhage on either CT or MRI is strongly suggestive of an underlying neoplasm, but contrast enhancement may be absent, particularly if the tumor is small and/or compressed or replaced by the hematoma. Evolution of blood products' signal characteristics on MRI tends to be delayed in neoplastic hemorrhages compared to the other etiologies. In the subacute stage, the T1 hyperintensity due to the presence of methemoglobin tends to be centrally located, just the opposite from nontumoral bleeds in which increased signal begins at the periphery and progresses inward. In addition, while edema surrounding other hemorrhages usually begins resolving within a week, edema will persist in the presence of a neoplasm. Lack of a complete hemosiderin ring around the periphery of a resolving hematoma after a few weeks is suggestive of tumor, but this is an inconsistent finding.