Male, 68 years old, history of renal cell carcinoma with solitary brain metastasis status post resection and postoperative radiation, surveillance scan. Findings are seen compatible with prior left frontal craniotomy, tumor resection and hematoma evacuation. An extra-axial fluid collection seen previously subjacent to the craniotomy has resolved. T2 hyperintensity within the left frontal lobe, surrounding the resection cavity, has improved when compared to the immediate postoperative examination. The cavity itself is hemosiderin stained and demonstrates gyriform intrinsic T1 hyperintensity compatible with laminar necrosis.Within the superior aspect of the cavity, an enhancing, hemosiderin stained nodule is identified measuring 11 x 7 mm (image 49 series 11). This lesion seems to correlate with a T1 hyperintense oval structure on the prior radiation planning examination which at that time measured 17 x 15 mm. It is unclear if this lesion enhanced on that prior exam as no precontrast images were obtained. The lesion also correlates with an area of blood product and mild adjacent enhancement seen on the immediate postoperative examination.No new intracranial lesions are seen. No new or significant parenchymal mass effect is detected. The left frontal horn has reexpanded with improvement in surrounding parenchymal edema, and the ventricular system is otherwise unremarkable.
1.Demonstration of findings compatible with left frontal tumor resection and hematoma evacuation. Acute postoperative findings have resolved, and the degree of diffuse abnormal signal surrounding the resection cavity has improved.2.Within the resection cavity, however, an enhancing, hemosiderin stained nodule is identified. This lesion seems to correlate with an oval T1-bright structure on the prior RT planning exam, and with a small collection of blood product and mild adjacent enhancement on the immediate postoperative MRI. The differential for this finding would therefore include an organized hematoma with fibrovascular or granulation tissue accounting for the enhancement, as well as a nodule of treated residual tumor.