Male, 73 years old, history of metastatic melanoma with enlarging brain metastasis, treatment planning MRI. A new large parenchymal hemorrhagic lesion is identified within the right frontal lobe which demonstrates markedly heterogeneous internal characteristics. The lesion overall shows prominent susceptibility compatible with blood product, with areas of scattered T1 hyperintensity as well as T2 iso- and hyperintensity. The main portion of this lesion shows no clear evidence of enhancement outside of the scattered areas of intrinsic T1 hyperintensity. Adjacent to the left anterior aspect of this lesion, and perhaps contiguous with the overlying dura, there is a small triangular region of tissue which does show some degree of enhancement above and beyond its intrinsic T1 hyperintensity. The lesion as a whole measures 48 x 39 mm (image 89 series 7), and the much smaller enhancing portion measures 13 x 11 mm (image 86 series 9).The above described lesion generates fairly significant parenchymal edema with regional mass effect in the form of sulcal effacement, mild subfalcine herniation, and mass effect on the right lateral ventricle.Redemonstrated is a resection cavity at the convexity of the left frontal lobe which appears unchanged. An additional hemosiderin stained, intrinsically T1 hyperintense lesion within the paramedian right parietal lobe is smaller, now measuring no more than 9 x 7 mm, previously 19 x 13 mm.
1. A new large hemorrhagic lesion is identified in the right frontal lobe. The bulk of this lesion shows patchy heterogeneous signal compatible with evolving blood product, but no definite superimposed enhancement. Only a small triangular shaped region of tissue along the left anterior aspect of the lesion, abutting the overlying dura, shows convincing evidence of enhancement. It is therefore not entirely clear how much of this lesion may represent viable metastatic tumor versus tumoral hemorrhage.2. Stable left frontal lobe resection cavity.3. Interval decrease in size of a lesion in the right parietal lobe.