72 years, Male, Reason: 72M with history of sigmoid colon cancer. treated with 3 courses of radiation therapy, most recently 7/2014, to a presacral recurrence. now with moderate pain in the left pelvis and left leg. evaluate for tumor recurrence vs radiation toxicity. History: left leg pain along L4 distrubution.. PELVIS: PROSTATE, SEMINAL VESICLES: No significant abnormality notedBLADDER: Diffuse bladder wall thickening may be secondary to radiation change..LYMPH NODES: No significant abnormality noted.BOWEL, MESENTERY: No significant abnormality noted.BONES, SOFT TISSUES: There is significant patchy enhancement, diffusion restriction and increased T2 signal throughout the sacrum, which is also low signal on precontrast T1 images of lumbar spine performed on the same day. This corresponds to region of minimally increased uptake on prior PET/CT. Overall, the signal changes mostly confined to the sacrum and only minimally extends to the left iliac bone. No definite fractures are evident in these images.There is also edema and enhancement which extends along the left piriformis and is thought to be reactive.OTHER: No significant abnormality noted.
1.Patchy enhancement and edema throughout the sacrum. Radiation changes are favored, however on the basis of these images, neoplasm cannot be excluded. It should be noted that it would be considered highly unlikely to have an isolated sacral metastases in the setting of colon cancer without other more common metastatic lesions.2.Edema and enhancement extending along the left piriformis thought to be reactive, unlikely to represent tumor.