The large bowel obstruction that was evident on the plain films is confirmed at CT.  The transition point is deep within the pelvis and takes the form of a smooth 4cm long stricture.  There is no mass or features that suggest malignancy. 

A secondary area of abnormality is noted within the descending/proximal sigmoid colon.  It has wall thickening and some narrowing, but is not causing the obstruction and again, looks inflammatory.

Relative incompetence of the ileocecal valve with partial decompression of the large bowel which still measures 7 cm at points.

Hysterectomy and bilateral oophorectomy noted.  The vaginal vault sits adjacent to the smooth stricture.  No nodal disease or features suggesting metastasis.

On balance, the stricture was considered benign and thought to be secondary to the previous radiotherapy that the patient received for her gynecological malignancy 10 years previously.

Diagnosis
Radiation-induced sigmoid stricture with large bowel obstruction.