Solitary Rectal Ulcer syndrome

Solitary rectal ulcer syndrome is a rare benign clinical entity of not entirely clear etiology. The term ulcer is more of a terminus technicus, it may be a solitary ulcer, but more lesions can be caught. Mucosal ulceration may not even be detected, but mucosal hyperemia or flat polyps, for example. The actual diagnosis is based on a combination of the clinical picture, endoscopic findings, and histopathological findings.

History
The first probable cases were described by the Fracnou anatomist and pathologist Jean Cruveilhier (1791–1874) as cases of unusual rectal ulcers. The term "solitary rectal ulcer syndrome" was first used in the late 1930s by the British surgeon Oswald Vaughan Lloyd-Davis (1905–1987) working in St. Mark in London. A more detailed description of a series of 68 patients was published in 1969 by MRMadigan and BCMorson of the same institution. This seemingly small series covers cases identified in St. Mark between 1931 and 1967. Finally, KRRutter and RHRiddell published in 1975 a comprehensive concept of pathogenesis as a disorder that occurs when rectal prolapse.

Epidemiology
The frequency of the disease is estimated at 1 per 100,000 inhabitants, but it will probably be higher due to underdiagnosis. It usually occurs in young adults but has also been described in children and the elderly. Disabilities of both sexes are about the same, with a probably insignificant predominance of disabilities in women.

Due to the rarity of the disease, a solitary rectal ulcer is usually not considered and the diagnosis can be made quite a long time from the beginning of the problem. According to published data, the time from the onset of difficulties to diagnosis ranges in a very wide range from three months to thirty years.

The clinical picture
Clinically, solitary rectal ulcer is manifested by rectal bleeding, abundant production and defecation of mucus (mucorrhea), strenuous defecation, abdominal or dam pain, feeling of incomplete emptying and constipation. Rectal prolapse may occur. Incontinence may occur in some patients. It is not completely rare or completely asymptomatic to have a solitary rectal ulcer accidentally found on examination for another reason.

Pathogenesis
The etiology and pathogenesis of the disease are not fully understood. The initial step in the development of a solitary rectal ulcer is thought to be mucosal damage by direct trauma or local ischemia. The original theory of Rutter and Riddell assumed that the provoking factor was rectal prolapse, today other factors are being considered. For example, it has been shown that trauma to the rectal mucosa leads, for example, to squat defecation or, under certain circumstances, abnormal contraction of the puborectal muscle. A key step in pathogenesis is mucosal prolapse, which may not be clinically manifest in itself. Prolapse leads to blood congestion, edema, and in general to ischemic changes, which can result in ulceration.

Humoral regulation may also be involved in pathogenesis. In patients, blood flow through the rectal mucosa is reduced, which is similar to a flow disorder in impaired cholinergic signaling. Another possible explanation for the worse flow is the hypothesis of a small vessel disorder; in the histological picture, an increase in the ligament can be demonstrated.

Patients with solitary rectal ulcers have also been shown to have higher anal pressure, puborectal dyssynergia, and rectal hypersensitivity.

All of the above factors, and possibly some others, appear to play a different role in the development of a solitary rectal ulcer.

Endoscopic examination
The lesion is typically on the anterior wall of the rectum at a distance of 12 cm from the anocutaneous junction. The size of the lesion usually varies between 0.5 and 4 cm. Only one lesion is detected in 70 %, in the remaining cases, several lesions are detected. Endoscopically, lesions can present in several forms: For a correct diagnosis, it is necessary to compare the biopsy not only from the lesion itself but also from the surrounding macroscopically intact mucosa.
 * erythematous form (18 % of cases),
 * polyposis (25 % of cases),
 * ulcerative form (57 % of cases).

Histopathologic findings
The basic histopathological characteristics are common to all three macroscopic forms: The lesion usually has relatively poor inflammatory infiltration, but both acute and chronic inflammatory infiltration can be detected. If the lesion is exulcerated, it may be covered by a pseudomembrane.
 * fibromuscular obliteration of the lamina propria mucosae,
 * hypertrophic muscularis mucosae with a spread of muscle bundles between crypts,
 * crypt distortion and hyperplasia, focal dilatation described as diamond-shaped dilatation may be present,
 * mucus gland distortion and hyperplasia,
 * extended capillaries.

Differential diagnosis

 * Crohn's disease
 * Ulcerative colitis
 * Ischemic colitis
 * infection
 * malignancy

Therapy
Due to the not entirely clear etiopathogenesis and the small number of cases, all published recommendations are supported by more expert opinions than by a deep pathophysiological balance or solid statistical evidence.

Conservative therapy, which consists mainly of a diet high in fiber, possibly supplemented with volume laxatives, is considered essential. It is also recommended to change the patient's behavior so that he changes his defecation habits (less time on the toilet, reduction of effort during defecation, reduction of common laxatives), which can have a secondarily positive effect on the physiology of defecation. If education is not effective in this, biofeedback, based behavioral therapy is recommended as an effective option, although some studies question the added value of biofeedback.

Other procedures are not considered first-line therapeutic procedures:
 * Topical drug applications: sucralfate, salicylates, corticoids, sulfasalazine, mesalazine, topically fibrin.
 * Endoscopic procedures: thermoablation with argon laser.
 * Surgical procedures: transanal excision with an operating rectoscope, rectopexy, mucosal resection according to Delorm, perineal proctectomy according to Altemeier, stapler transanal rectal resection.

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