Solitary rectal ulcer: ultrasonographic and magnetic resonance imaging patterns mimicking rectal cancer

The objective of this study was to analyze a series of solitary rectal ulcer syndrome (SRUS) cases initially diagnosed as rectal cancer. We analyzed all the patients (1996-2008) initially referred to our colorectal unit with a diagnosis of rectal cancer but with a final diagnosis of SRUS. Demographic data, the diagnostic work-up, and treatment details were collected in a prospective database and analyzed retrospectively. Out of the 5035 patients registered in the colorectal unit database, 14 (0.28%) had a final diagnosis of SRUS. Nine of them had an initial diagnosis of rectal cancer. Out of these, six were preoperatively staged with endorectal ultrasound and/or magnetic resonance and were therefore analyzed for this study. Endorectal ultrasound was performed in all six patients and rectal cancer was diagnosed in five of them; MRI was performed in four patients and a diagnosis of rectal cancer was assessed in three of them; rectal cancer was finally ruled out in all cases by deep-forceps macrobiopsies. The incidence of misdiagnosis between SRUS and rectal cancer does not decrease with the regular use of imaging methods. Clinical judgment and deep-forceps macrobiopsies are essential in avoiding an erroneous diagnosis.