History of metastatic thyroid cancer with brain metastases status post SRS for surveillance. A lesion has developed within the left inferior parietal lobule measuring 14 x 12 mm with heterogeneous T2 bright signal on a background a strong susceptibility and probable mild rim and speckled enhancement. This lesion is associated with significant new FLAIR signal abnormality. On the prior examination, only a punctate enhancing focus was seen at this location. Anterior to the above lesion within the left superior parietal lobule is an enhancing lesion which measures 7 x 5 mm, previously 7 x 7 mm. There is slightly increased associated FLAIR signal abnormality.The punctate left inferior frontal gyrus enhancing lesion is unchanged. This lesion also demonstrates mild susceptibility effect which is unchanged. The punctate focus of enhancement within the left lateral post central gyrus is also unchanged. The left anterior temporal lobe lesion is decreased in enhancement, and is associated with hemosiderin staining.The right anterior inferior frontal gyrus enhancing lesion measures 6 x 4 mm, previously 6 x 5 mm. The surrounding FLAIR signal abnormality is similar to the prior exam. An additional punctate enhancing lesion noted in the right middle frontal gyrus is unchanged. The lesion along the lateral aspect of the junction between the body and frontal horn of the right lateral ventricle, now measures up to 3 mm, previously 6 mm. There is an associated new focus of susceptibility. There is no definite new lesion. No significant mass effect, midline shift or herniation. There are no extraaxial fluid collections. Incidental note is made of a partially empty sella which is a normal variant. Moderate bilateral ethmoid sinus opacification. Bilateral maxillary mucous retention cysts.
1. Interval development of a heterogeneous, minimally enhancing lesion containing blood product within the left inferior parietal lobule, the site of a previously seen punctate focus of enhancement. This newly developed lesion could represent a simple intralesional hemorrhage, or perhaps a radiation related cavernoma, with associated significant surrounding edema. A growing metastasis, while on the differential diagnosis, is considered somewhat less likely given the overall stability or improvement of numerous other lesions. 2. An adjacent smaller left superior parietal lobule metastatic lesion with slight increase in the surrounding FLAIR signal, but decreasing enhancement, is favored to reflect treatment effect. 3. Interval decrease in the size of a right lateral ventricle lesion. Interval decrease in enhancement in a left temporal lobe lesion now with hemosiderin staining, perhaps representing treatment effect.3. Stable size of the remaining lesions. No definite new lesions.