RADIOLOGY: GASTROINTESTINAL: GI: Case# 32802: RECTAL CA. The patient is a 72-year-old female. 5 cm rectal mass with broad base attachment to the left posterior lateral rectal wall. Although there are no obviously enlarged lymph nodes or evidence of metastases, there are considerable strandy changes in the perirectal fat on the left and posteriorly which is worrisome for tumor infiltration.