Anal Canal Epithelium Research Articles

Water Stream in Bidet Toilet Commode as a Cause of Anterior Anal Fissure: A Case-Control Study

Background: Water used as a single sharp stream in toilet commode for post defecation cleansing is a common practice in several countries across the globe including India. Repeated hitting of the anus by water stream could potentially cause injury to the anal canal epithelium and lead to development of fissure-in-ano. As the water stream is emanating from the backside of the toilet commode, the possible injury, if any, would be on the anterior anal canal.Objectives: The present study aimed at determining whether water stream usage in toilet commodes increased the incidence of anterior fissure-in-ano; this was determined by the incidence of anterior fissure-in-ano the study and control groups.Methods: All consecutive fissure-in-ano patients referring to a colorectal clinic from February 2012 to 2015 were included in the study. The patients were classified as a study group (who were using water stream for cleansing purposes in toilet commodes) and a control group (patients who were not using water stream). The characteristics and location (position) of the fissure-in-ano wasnoted.Results: In this study, 165 patients were prospectively enrolled. Male/female ratio was 96/69, and the mean age was 36.3±11.2 years.The anterior fissure-in-ano in the study group was 55.9% (47/84), while it was 17.3 % (14/81) in the control group (P < 0.0001, oddsratio: 6.08, 95% CI: 2.96 - 12.47].Conclusions: Water used as a single sharp stream to cleanse after defecation in toilet commodes is hazardous and should be avoided.

Primary Signet Ring Cell Anal Adenocarcinoma

Anal cancer is a rare neoplasm accounting for 1.2–2% of all digestive cancers [1, 2] but presents with an increasing incidence. The carcinoma of the anus has a female predominance and usually presents in patients at or over the age of 65 [1–3]. Epidermoid carcinoma and predominantly squamous cell carcinoma, account for more than 70% of all cancers of the anus [3], while adenocarcinoma is less common comprising for about 5–19% of anal carcinomas [3, 4]. Anal adenocarcinoma is a carcinoma of the anal canal epithelium and there are three major types: the rectal type adenocarcinoma arising from the mucosal surface, the anal gland adenocarcinoma and the adenocarcinoma associated with anal fissures and anorectal fistula, usually of the mucinous type [1, 3, 5]. Signet ring cell anal adenocarcinoma is extremely rare with only one case reported in the literature [6]. We present a case of signet ring cell adenocarcinoma (SRCA) of the anus.

Initial Experience with Topical Fluorouracil for Treatment of HIV-Associated Anal Intraepithelial Neoplasia

Exposure to high-risk strains of human papillomavirus (HPV) promotes cellular dysplasia of the anal canal epithelium, potentially leading to anal intraepithelial neoplasia (AIN), which is in turn a precursor to invasive squamous cell carcinoma of the anus (SCCA). People with HIV infection who engage in anoreceptive intercourse are at heightened risk for acquiring HPV, AIN, and SCCA. Although intravenous 5-fluorouracil (5-FU) is commonly used for treatment of invasive SCCA, there has been little experience with the use of topical 5-FU as therapy for AIN. We retrospectively reviewed records of the first 11 HIV-positive patients treated with topical 5-FU in our anal dysplasia clinic. Six (55%) patients had clinical improvement with reduction in area of dysplasia seen on high-resolution anoscopy (HRA). Three (27%) patients had improvement in AIN pathologic grade. Eight (73%) patients reported mild-to-moderate perianal irritation, which led six to reduce the frequency of 5-FU application. Further study of topical 5-FU for treatment of HIV-associated AIN is warranted.

Submucosal electrocoagulation for prolapsed hemorrhoids:a new operative approach to hemorrhoidal varices.

The results of submucosal electrocoagulation (SEC), a new radical operation for prolapsed hemorrhoids, in 403 patients with third- or fourth-degree hemorrhoids are reported. After resecting the anal skin tags that coexisted with prolapsed hemorrhoids, the hemorrhoidal varices could be resected and electrically coagulated through the wound without cutting the anal canal epithelium by using a fine needle-type electric knife. The results of this series indicated that SEC could dramatically reduce the incidence of the postoperative complications that sometimes occur after conventional hemorrhoidectomy, such as severe anal pain, massive anal bleeding and anal stenosis. Moreover, SEC could ensure that operated patients make an early return to social activities and have a satisfactory quality of life. Relapse of prolapsed hemorrhoids after SEC was rare.

A Lesion on Rectal Retroflexion

Question: A 77-year-old woman presented with chronic constipation and intermittent episodes of painless hematochezia related to “hemorrhoids.” Prior colonoscopies were unrevealing. On digital rectal examination, no lesions were palpated. A colonoscopy was performed, which was unremarkable; there were no lesions seen as the colonoscope was withdrawn through the rectum and anal canal area. However, retroflexion of the instrument within the rectum demonstrated a distal rectal lesion (Figure A). It was unclear if this polypoid lesion was originating from the rectum or the anal canal. Given its proximity to the dentate line, it was biopsied (Figure B). What is the diagnosis? See the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. Figure B shows the histopathology of Bowen's disease (also known as squamous cell carcinoma in situ) with atypical squamous cells which have abundant eosinophilic cytoplasm and large nuclei. Carcinoma in situ is a noninvasive lesion defined as having malignant cells that have not penetrated the basement membrane. The condition was originally described by John T. Bowen in 1912.1Bowen J.T. Precancerous dermatoses: a study of two cases of chronic atypical epithelial proliferation.J Cutan Dis Syph. 1912; 30: 241-255Google Scholar Bowen's disease is used to refer to a dysplastic condition of the anal canal epithelium. However, the term “Bowen's disease” is not clearly defined in the literature and other terms used to describe dysplastic anal canal lesions include anal squamous intraepithelial lesions or anal intraepithelial neoplasia. As in our patient, anal bleeding is the most common symptom of anal canal carcinoma.2Ryan D.P. Compton C.C. Mayer R.J. Carcinoma of the anal canal.N Engl J Med. 2000; 342: 792Crossref PubMed Scopus (358) Google Scholar There is disagreement regarding the best treatment for Bowen's disease.3Chang G.J. Welton M.L. Anal neoplasia.Semin Colon Rectal Surg. 2003; 14: 111Abstract Full Text Full Text PDF Scopus (11) Google Scholar Our patient was treated as invasive T2 anal cell carcinoma with combined radiation and chemotherapy, because it was suspected that there was likely an invasive component given that the lesion involved one third of the circumference of the anorectal ring. One year later, she has no evidence of residual or recurrent disease. This case highlights 2 important points. First, painless rectal bleeding from anal squamous cell carcinoma can mimic hemorrhoidal bleeding and episodes of painless rectal outlet bleeding should not be attributed to internal hemorrhoids without an anoscopic examination. Second, this lesion would have been missed if the retroflexion maneuver had not been performed, thus illustrating the usefulness of rectal retroflexion in detecting neoplastic lesions.

Initial experience with topical fluorouracil (5-FU) for treatment of anal intraepithelial neoplasia (AIN) in HIV-positive patients

Background Exposure to certain strains of human papilloma virus (HPV) promotes dysplasia in cells of the anal canal epithelium, leading to AIN, which is in turn a precursor to squamous cell carcinoma of the anus (SCCA). Patients with HIV infection who have anoreceptive intercourse are at heightened risk for acquiring HPV, AIN, and SCCA. The use of topical 5-FU to prevent the progression of lower genital tract neoplasia to invasive cervical carcinoma has been studied in both HIV+ and HIV- women. Although intravenous 5-FU is also commonly used for treatment of invasive SCCA, there has been little experience with the use of topical 5-FU as therapy for AIN. Materials and methods We retrospectively reviewed medical records from our anal dysplasia clinic. Our study population comprised 11 HIV+ men with biopsy-proven AIN who were treated with topical 5-FU. All patients were initially instructed to apply a pea-sized amount of topical 5-FU to the anus each night, to wash their hands afterwards, and to wipe away excess 5-FU in the morning. Patients reduced the frequency of application if they experienced undue local irritation. Results

Abnormal Advanced Hemorrhoidal Disease: The Need of a Staged Resection

We present an unusual case of advanced hemorrhoidal disease in an 57-year-old man presenting with anemia, persistent bleeding, anal protrusion. Conventional hemorrhoidectomy was not feasible because of the risk of a massive hemorrhage caused by hypertrophic protruded vascular anal cushions. A two-stage resection was then undertaken. The aim of the first procedure was to reduce the vascularization of the protruded mucosa by a circular series of interrupted mass stitches. This approach was successful and an important reduction of vascularization was obtained. The operation was then completed two weeks later, requiring a radical circular removal of the giant anal cushions and anal canal epithelium with subsequent mucocutaneous anastomosis. A careful submucosal dissection was performed to identify and preserve the anal sphincters. No normal perianal skin was available to preserve bridges between the resected cushions. At the end of the operation, an ectopic mucosa was apparent but gradual reduction was observed in subsequent postoperative days along with recovery of anal sphincter function, and the patient was uneventfully discharged on the seventh postoperative day. On the 30th postoperative day a normal anal canal closure was observed with no ectopic mucosa. Normal continence with no functional disorder was reported and digital examination demonstrated the presence of a mild asymptomatic stenosis. (See Video, Supplemental Digital Content 1, http://links.lww.com/DCR/A1).

Treatment of anal intraepithelial neoplasia.

The natural history and malignant potential of anal intraepithelial neoplasia (AIN) remain uncertain, making management decisions about such lesions difficult. The management of 70 patients with AIN is described. The majority of lesions encountered were low grade (AIN I and II; 43 of 70) and required no treatment, but eight invasive anal cancers associated with high-grade AIN occurred over the 4-year study period. Three were a result of apparent progression of high-grade lesions; three more invasive lesions were found in areas of AIN III on histological examination. Surgical excision was used to treat 27 patients with AIN III. Treatment of extensive lesions involving the perianal and anal canal epithelium circumferentially in six patients involved excision of the whole of this epithelium and application of split skin grafts.

Ultrastructural studies on the anal canal epithelium in the mouse, with special reference to the keratinizing process.

The stratified squamous epithelium lining the mouse anal canal revealed various stages of keratinization. Considering the ultrastructural features, it is suggested that the epithelium lining the distal part shows more advanced keratinization than in the proximal part. Further, the width of the microridges in the distal part was about doubled compared to that in the proximal part. The difference in the width of microridges appears to be an important marker of the degree of keratinization.

Endocrine cells and melanin-containing cells in the anal canal epithelium.

The epithelium of the anal canal from 22 humans was studied in order to demonstrate the possible presence of endocrine cells and melanin-containing cells. Histochemical methods aimed at demonstrating reducing substances, biogenic amines, argyrophilia and melanin, were used. Enterochromaffin cells, and possibly other types of endocrine cells, were demonstrated above the dentate line both in colo-rectal type epithelium and in the anal transitional zone. Melanin-containing cells could also occasionally be found in the anal transitional zone. The presence of endocrine cells in the anal canal epithelium opens up the possibility that carcinoids can originate in this region. Further, the presence of melanin-containing cells might explain the occurrence of malignant melanomas arising above the dentate line.

Ultrastructure and chloride cytochemistry of the hindgut epithelium in the larvae of the seawater mosquito, Aëdes togoi Theobald.

The hindgut of Aëdes togoi larvae adapted to various external salinities was studied by light and electron microscopy. The larvae's pyloric chamber and the ileum of the hindgut are surrounded by a thick muscular layer and lined with a very thin unspecialized epithelium. There is no detectable difference in the ultrastructural organization of the epithelium between seawater-adapted and freshwater-adapted larvae. The rectum and the anal canal are greatly dilated and densely tracheated and have a very thick, highly specialized epithelium. The rectal epithelium is characterized by shorter apical and longer basal infoldings closely associated with mitochondria, and a particulate coating on the apical infoldings. The intercellular spaces and the basal channels are tightly closed in the rectal epithelium of freshwater-adapted larvae, whereas widely dilated in that of 100 to 200% seawater-adapted larvae. The rectum seems to reabsorb water from excretory fluid when larvae are in hyperosmotic media. The anal canal epithelium possesses well-developed apical infoldings, which are coated with small particles an intimately associated with mitochondria. The basal infoldings are short. No perceptible difference in the ultrastructural organization of the epithelium was observed between seawater-adapted and freshwater-adapted larvae. The lumina of the apical infoldings of the anal canal epithelium in seawater-adapted larvae, however, demonstrated a strongly positive reaction to the cytochemical assay for chloride ions, whereas the reaction was very weak in freshwater-adapted larvae. Unlike salt-water-mosquito larvae of the other species, in which the rectum is considered to be concerned with the formation of hyperosmotic urine, the anal canal in A. togoi larvae seems to play an important role in excretion of excess ions in the haemolymph when adapted to hyperosmotic media.

Mucin histochemistry of the anal canal epithelium. Studies of normal anal mucosa and mucosa adjacent to carcinoma.

The epithelial lining of the anal canal is of colo-rectal type in the upper part and squamous in the lower part, while the middle zone is called the anal transitional zone (ATZ). This zone is characterized by an epithelium which bears a resemblance to that of the anal glands and shows little mucus secretion. The histochemical properties of the mucins in the epithelium of 39 anal canals, resected for ano-rectal adenocarcinoma, basaloid carcinoma, squamous carcinoma and malignant melanoma were investigated. The study reveals that (1) the mucin composition of the ATZ epithelium corresponds to that of the anal glands, being characterized by a mixture of sulpho- and sialomucins with scarcity or absence of O-acylated sialic acids; and (2) cases with carcinomas located near the dentate line show changes in the mucin composition of the adjoining anal canal epithelium, regardless of tumour type. In colo-rectal type mucosa, these mucins consist of increasing amounts of sialomucins with a predominance of N-acyl derivatives, and in the anal glands of increasing amounts of sulphomucins and O-acyl derivatives of sialomucins. No changes could be detected in the ATZ epithelium. It is concluded that rectal and anal glands in the anal canal are exposed to stimuli which alter the normal process of glycoprotein synthesis and secretion. The changes seem to be secondary to tumour growth and independent of the histological type of tumour.