SRUS is a chronic disorder which can present with diverse endoscopic findings. Since diagnosis on the basis of clinical symptoms alone is difficult, it is imperative for the clinicians to keep this entity in their differentials on endoscopic examination to reach the correct conclusion. Incidences of under and misdiagnosed cases have been reported in literature [3
]. Much of the lapse in diagnosis is ascribed to the lack of familiarity of clinicians with endoscopic revelations and the actual condition associated with SRUS. A typical solitary rectal ulcer is a shallow based ulcerating lesion encircled by hyperemic mucosa [8
]. This study to the best of our knowledge is the largest series of patients with SRUS. It met with intriguing diversity in the appearance of these lesions from being plain ulcerative to polypoidal and from presenting as an erythematous mucosa to multiple ulcerative lesions. Other interesting findings included multiple telengectatic bleeding spots (Figure
) and a large lesion lying in close proximity of a cancerous rectal polyp (Figure
The findings in the present series correspond with the literature in terming SRUS as a misnomer. The polypoid or nodular variant of SRUS has a higher tendency to be misdiagnosed and confused with other presentations for instance those of inflammatory polyp, hyper plastic polyp or rectal carcinoma [3
]. Hence, variability with which SRUS presents on endoscopy is more profound than is generally comprehended.
Histopathological analysis forms the cornerstone of diagnosing SRUS and is a requisite to rule out any other underlying disease. In contrast to the inconsistency and discrepancy on clinical and endoscopic findings, histological characteristics associated with SRUS are well documented. Key histological features encompass fibromuscular obliteration of the lamina propria with splaying of muscularis mucosae upward between the crypts, thickened mucosa and glandular distortion [9
]. These features are also seen to be overlapping in other benign defecation disorders including rectal prolapse, PCP and inflammatory cloacogenic polyp [10
]. Our study revealed fibromuscular obliteration in all patients, with 59% additionally having surface ulceration. Other findings such as mucosal glands and crypts distortion were less documented. In contrast, a study documented all 13 patients having crypts distortion and surface serration [2
]. Moreover, no inflammation was seen in majority of the lesions in our series and when present, inflammatory infiltrates were usually found to be mild in character. Nonspecific histological findings may be apparent on SRUS lesions which include hyperplastic and distorted crypts together with epithelial atypia and high degree of inflammation [18
]. These findings along with similar symptomatology and variable endoscopic findings can make it challenging at times to differentiate SRUS from IBD.
Three patients had a history of ulcerative colitis in the current series. Development of SRUS in patients with past history of ulcerative colitis can lead to confusion whether the patient’s symptoms are due to an exacerbation of the primary disease or because of SRUS. In another study, seven patients of SRUS were at first misdiagnosed for IBD [3
] while cases of SRUS in patients with history of ulcerative colitis have also been reported [21
]. However, fibromuscular obliteration and excess mucosal collagen helps in differentiating SRUS from IBD on morphological analysis [23
]. ‘Diamond shaped crypts’ have also been seen to be an important finding in diagnosing SRUS. A study comprising a cohort of 32 patients with SRUS revealed diamond shaped crypts in all the patients as compared to only one case of IBD while another study reported over half the patients having this feature on histological analysis [3
Studies emphasize that histopathology of SRUS may be associated with a deeper concealed malignancy [25
]. In one of the study it was documented that malignant tumors might present with histological findings suggesting SRUS initially and later develop characteristics of malignancy which suggests SRUS has the potential to progress to malignancy [25
]. Another study reemphasizes this aspect by demonstrating loss of hMLH1 gene expression in several cases of SRUS indicating the possibility of neoplastic progression [27
]. A case of well differentiated infiltrating adenocarcinoma in the focus of SRUS has also been reported and the authors speculated that there is a chance of adenocarcinoma originating from SRUS mucosa [26
]. These observations from the available literature support findings in one of the case (Figure
) in our series. However, there could be a possibility of missing the neoplastic lesion initially in our case when the biopsy was taken the first time but it may reflect the simultaneous existence of SRUS with adenocarcinoma so it is emphasized to have a high index of suspicion and repeated examinations with multiple biopsies to be taken. Similarly, two other patients in present series demonstrated coexistence of SRUS with adenomatous polyps. However, it should also be emphasized that the neoplastic lesions of adenoma and adenocarcinoma have been reported as associations only with SRUS and that no causal relationship has been established yet from the data in the present literature.
Inconsistency in morphologic appearances of associated lesions increases the likelihood of delayed or erroneous diagnosis of SRUS [3
]. Our series depicted that rectal bleeding and abdominal pain were the most common complains. Large number of patients also complained of constipation and/or diarrhea while mucus per rectum and perianal pain were encountered less frequently. This corresponds to other studies published with similar complaints [2
]. BPR occurs most likely due to ulcerations or direct trauma to the mucosa. Manual digital evacuation is the other important factor causing direct injury to the rectal mucosa and possibly the cause of bleeding in SRUS [28
]. In our study, only eight patients were documented to perform rectal digitations. This low number of patients with history of digital evacuation of feces may be due to the retrospective nature of the data (poor documentation) or hesitation on the part of the patients in revealing it to the physician or unwillingness to have them documented in records. Another important point is the time span between onset of symptoms and establishment of a correct diagnosis in patients with SRUS which range from three months to 30
]. The time that elapses during this period might have important clinical consequences like weight loss and anemia as demonstrated in the present series that 22% of patients presented with anemia and 16% had weight loss at the time of diagnosis.