Short Occult Retractile Fibrous Scar Causing Exclusive Retrograde Stenosis of the Sigmoid Colon: An Incidental Diagnosis Nineteen Years After a Single Episode of Colonic Diverticulitis.

We report a rare case of purely retrograde stenosing stricture of the sigmoid descending colonic junction fortuitously diagnosed during the waning of a failed virtual colonoscopy in a 69-year-old patient. The rather asymptomatic patient was addressed to investigate a positive fecal occult blood test. He had suffered a single acute colonic diverticulitis episode 19 years before. A contrast-enhanced abdominal CT and complementary focused abdominal ultrasound fully diagnosed a short curvilinear contrast-enhancing "scar-like" tissue infiltrating the posterior colonic wall and developing retractile adherences with the retroperitoneum of the left iliac fossa. The imaging features are presented with pathologic correlation.