Mucosal prolapse syndrome: diagnosis with endoscopic US

To determine the value of endoscopic ultrasound (US) in the diagnosis of mucosal prolapse syndrome (MPS), also known as solitary ulcer of the rectum.

Three male and two female patients (age range, 17-66 years) with biopsy-proved MPS underwent endoscopic US. The average rectal wall thicknesses of the affected areas were compared with those of normal-appearing mucosa.

The gross appearance of the rectal lesions was classified into three types: polypoid (n = 2), flat (n = 1), and ulcerative (n = 2). In all three types of lesions, endoscopic US demonstrated smooth, diffuse thickening of the third layer of the rectal wall; the other layers had minimal thickening. Neither a solid hypoechoic mass nor a transmural infiltrating lesion was visible, and the five-layer structure of the rectal wall was completely preserved. In the polypoid lesions, the third layer was winding as well as thickened, and microcystic components were occasionally found.

Endoscopic US enabled differentiation of MPS from other conditions such as malignant neoplasia and Crohn disease.