Solitary Rectal Ulcer Syndrome (SRUS), also known as benign solitary rectal ulcer or benign nonspecific rectal ulcer, is a digestive disorder caused by acute or chronic benign solitary ulcers in the anterior rectal wall. It is characterized by symptoms such as abdominal pain, constipation, diarrhea, and bloody or purulent stools. This condition is relatively rare and predominantly affects middle-aged and elderly women.

bubble_chart Etiology

The cause of the disease is unknown. Some believe it is due to spastic contraction of the puborectalis muscle, which obstructs feces at the anorectal ring. To overcome this resistance, excessive straining during defecation is required, leading to rectal prolapse and ischemia-hypoxia of the anterior wall mucosa, resulting in ulcer formation. Others suggest that excessive perineal descent and injury to the pudendal nerve may also be significant factors in the development of this condition. Additionally, chronic constipation, insufficient blood supply to the intestinal mucosa, and drug or mechanical damage may also be related to the occurrence of this disease.

bubble_chart Clinical Manifestations

The onset is often gradual, with a history of chronic constipation or straining during defecation. The main clinical manifestations include abdominal pain, constipation, diarrhea, bloody and purulent stools, and thinning of stools. Abdominal pain is mostly located in the lower abdomen, perineum, or sacrococcygeal region, presenting as dull pain that worsens during defecation and alleviates afterward. Symptoms also include difficulty in defecation, tenesmus, bloody stools, mucous stools, or bloody and purulent stools. A few cases may exhibit alternating diarrhea and constipation. Rectal prolapse is often present. In rare cases, the onset is acute, related to stress factors, characterized by severe abdominal pain, hematochezia, and even life-threatening conditions such as acute massive bleeding, intestinal perforation, or intestinal necrosis.

1. Sigmoidoscopy or fiberoptic colonoscopy: On the anterior wall of the rectum 3-15 cm from the anus, solitary ulcers can be observed on the mucosa, appearing round or oval with a diameter of 0.2-0.8 cm. They are mostly single but can also be multiple, surrounded by nodular mucosal edema and elevation, with a lesion range of 1-4 cm. Ulcers can be divided into active and inactive stages. In the active stage, the ulcers are deeper with clear boundaries, covered by a thin layer of pseudomembrane, and surrounded by congestive edema, with some showing active bleeding. In the inactive stage, the ulcers are superficial, and there may be localized mucosal thickening, with a few cases leading to rectal stenosis.

2. X-ray contrast examination: Single or multiple rectal ulcers, intestinal lumen narrowing, and nodular changes in the mucosa can be observed.

3. Biopsy: Non-specific chronic inflammatory changes are present, with mucosal surface erosion and ulcer formation covered by pseudomembrane-like structures. The mucosal muscle layer is thickened, fibrous tissue proliferates between glands, and there is infiltration of lymphocytes and plasma cells. In advanced stages, rectal glandular cells show significant hyperplasia with certain heterogeneity and may migrate into the mucosal muscle layer and submucosal stroma, easily misdiagnosed as cancerous lesions.

bubble_chart Diagnosis

When clinical manifestations such as abdominal pain, diarrhea, bloody stools with pus, and constipation are present and cannot be explained by other intestinal disorders, the possibility of this condition should be considered. Diagnosis can be confirmed through X-ray or fiberoptic colonoscopy.

The main treatment is medical therapy. Patients should consume a high-fiber diet to maintain smooth bowel movements and use mild laxatives when experiencing difficulty defecating. Sitz baths with 1:5000 potassium permanganate solution should be applied, and anti-inflammatory medications should be taken in case of secondary infection. For severe cases unresponsive to medical treatment, local surgical excision may be performed, but recurrence is common. Patients with concurrent rectal prolapse may undergo rectal fixation. The condition usually follows a benign course, but there is a potential for malignant transformation.

bubble_chart Differentiation

The clinical presentation and pathological features of the advanced stage may resemble those of intestinal cancer and should be differentiated.