Sacral mass, renal cell carcinoma An ill-defined soft tissue mass is noted at the left sacral ala extending from S1 to S2 which represents the known metastatic lesion. The mass is slightly hyperintense to muscle on T1 and hyperintense to muscle on T2/STIR sequence and enhances homogeneously. The mass measures approximately 5.1 x 3.7 x 4.2 cm in the greatest transaxial and craniocaudal dimensions. There is encroachment upon the left S1 neural foramen with the S1 nerve root coursing through the mass and the S2 neural foramen is poorly visualized. Additionally, there is asymmetric enhancement of the dura at this level which may be reactive in nature however the possibility of direct involvement must be considered.No additional soft tissue lesions are identified. There is no suspicious marrow signal throughout the remaining pelvis and lumbar spine.Note is made of a cystic mass within the left hemipelvis measuring 4.9 cm in the region of the left ovary. This is likely functional in nature however given the patient's age, attention on follow-up is recommended. This was present on the outside CT dated 6/10/2016. A similar, smaller focus is seen in the right hemipelvis which is also in close proximity to the right ovary.
1. Ill-defined soft tissue mass involving the left sacral ala consistent with known biopsy-proven metastatic focus. There is encroachment upon the left S1 neural foramen with poor visualization of the S2 neural foramen, concerning for direct invasion. Additionally, there is asymmetric enhancement of the dura which may be reactive in nature although the possibility of malignant involvement must also be considered.2. No additional soft tissue masses or abnormal marrow signal within the pelvis.3. Cystic foci within the pelvis are likely ovarian and functional in nature however given the patient's age, attention on follow-up is recommended.