(See also Evaluation of Anorectal Disorders.)
Solitary rectal ulcer syndrome is caused by mucosal ischemia of the distal rectal mucosa resulting from trauma.
Paradoxical contraction of the puborectalis muscle
Attempts at manual disimpaction of hard stools
Affected patients have straining during defecation, a sense of incomplete evacuation or pelvic fullness, and sometimes passage of blood and mucus by rectum.
The syndrome is poorly named because associated lesions may be solitary or multiple and ulcerated or nonulcerated; they range from mucosal erythema to ulcers to small mass lesions. Lesions are typically located in the anterior rectal wall within 10 cm of the anal verge.
Diagnosis of solitary rectal ulcer syndrome is typically made by clinical history alone, but flexible sigmoidoscopy with biopsy is sometimes done for confirmation. Assessment for internal or full-thickness rectal prolapse should be done (see diagnosis of rectal prolapse).
Histopathologic examination of the biopsy specimen shows a thickened mucosal layer with distortion of the crypt architecture and replacement of the lamina propria with smooth muscle and collagen, leading to hypertrophy and disorganization of the muscularis mucosa.