We report the case of an 84-year-old woman with histiocytic sarcoma arising in the terminal ileum. The lesion was identified on CT of the abdomen as a 10 cm segment of terminal ileum with mild circumferential wall thickening, isoattenuation, and diffuse homogeneous enhancement. The patient was treated with surgery and adjuvant chemotherapy. This case provides an example of when imaging may be useful for the detection of this rare malignancy and its complications.