A stem cell population at the anorectal junction maintains homeostasis and participates in tissue regeneration

At numerous locations of the body, transition zones are localized at the crossroad between two types of epithelium and are frequently associated with neoplasia involving both type of tissues. These transition zones contain cells expressing markers of adult stem cells that can be the target of early transformation. The mere fact that transition zone cells can merge different architecture with separate functions implies for a unique plasticity that these cells must display in steady state. However, their roles during tissue regeneration in normal and injured state remain unknown. Here, by using in vivo lineage tracing, single-cell transcriptomics, computational modeling and a three-dimensional organoid culture system of transition zone cells, we identify a population of Krt17+ basal cells with multipotent properties at the squamo-columnar anorectal junction that maintain a squamous epithelium during normal homeostasis and can participate in the repair of a glandular epithelium following tissue injury.

A DESCRIPTIVE STUDY OF MR DEFECOGRAPHY FOR EVALUATION OF OBSTRUCTED DEFECATION SYNDROME

Objective:-This study aims to ascertain the role of MR Defecography in the evaluation of obstructed defecation syndrome (ODS) with objective to describe spectrum of MR Defecography findings in obstructed defecation syndrome (ODS) and describe a number of reference lines and measurement points used to diagnose and grade pelvic floor disorders and Document the MRI appearance of disorders associated with ano-rectal dysfunction. MR Defecography demonstrated the profile of obstructed defecation syndrome on the basis of MR defecography and demonstrate its utility in simultaneous & objective evaluation of all three pelvic compartments. This diagnostic modalities provide a detailed pelvic floor anatomy and functional evaluation, as well as their respective abnormalities, making a precise diagnosis and provides valuable information on treatment planning & decrease chance of postoperative recurrence. Subjects and Methods: It was Cross-sectional and prospective (quantitative) hospital based descriptive type of observational study carried out at a tertiary hospital SMS hospital, jaipur. Chosen the patients diagnosed with ODS as per Rome criteria (III) whose colonoscopy or rectosigmoidoscopy, had been done to rule out other findings from Feb 2018 to September 2019.MR defecography (static and dynamic) with 3 T (PHILIPS INGENIA) MRI system having tunnel configuration. After written and informed consent, patient was positioned supine in MR machine gantry . Static imaging performed in the axial T1WI high resolution, axial, coronal and sagittal T2WI high resolution images at rest for anatomical evaluation. Following this,after ultrasound gel instilled in the patient’s rectum and intravaginaly ,dynamic imaging were taken in the midsagittal plane through the anal canal using a T2 weighted sequence. This sequence was ran for almost 2 min, while the patient performs various maneuvers (Kegel (squeeze), valsalva menuvere (strain), and defecation). MR defecography structurally and functionally evaluated in all 3 pelvic floor compartments and associated defects noted and grading of specific findings like organ specific prolapse, pelvic floor relaxiation and descent were measured. Results: In our study most common findings were pelvic floor descent and anorectal junction descent in 92.68% cases each followed by rectocele in 82.93% cases. Among the females, vaginal/uterine prolapse were observed in 65.31% cases. Least common findings were paradoxical contraction (8.54%) and sigmoidocele (0%). Significant difference was observed in MRI functional parameters in resting state and during defecation/maximal strain position, utilising HMO system for pelvic floor relaxation and descent, as significant difference (p <0.001S) was observed in all parameters including H line, M line, bladder base descent, cervical/vaginal and anorectal junction descent during resting state and during defecation/maximal strain position. Out of 82 conservative biofeedback therapy was given to 79.27 % patients, surgical management was done in (7.32%) and combination of both therapies was given in 13.41% of cases. Out of 82 patients 68.29% showed benefit from management and showed improvement on follow and 31.71% patients were not improved on follow up. Conclusion: As complete survey of the entire pelvis is necessary before surgical repair Magnetic resonance imaging permits evaluation of all three pelvic compartments and as we demonstrated in our study more than one compartment are frequently affected in obstructed defecation syndrome. Static MR Imaging can be also useful to identify the defects responsible for pelvic organ prolapse and stress urinary incontinence, and so help perform site specific repair in surgery, to avoid the high recurrence rates.Findings reported at dynamic MR imaging of the pelvic floor are valuable for selecting candidates for surgical treatment and for indicating the most appropriate surgical approach as detection rate of pathologies increased during defecation / maximal straning as concluded by our study.

Endoscopic mucosal resection is effective for laterally spreading lesions at the anorectal junction

ObjectiveThe optimal approach for removing large laterally spreading lesions at the anorectal junction (ARJ-LSLs) is unknown. Endoscopic mucosal resection (EMR) is a definitive therapy for colorectal LSLs. It is unclear whether it is an effective modality for ARJ-LSLs.DesignEMR outcomes for ARJ-LSLs (distal margin of ≤20 mm from the dentate line) in comparison with rectal LSLs (distal margin of >20 mm from the dentate line) were evaluated within a multicentre observational cohort of LSLs of ≥20 mm. Technical success was defined as the removal of all polypoid tissue during index EMR. Safety was evaluated by the frequencies of intraprocedural bleeding, delayed bleeding, deep mural injury (DMI) and delayed perforation. Long-term efficacy was evaluated by the absence of recurrence (either endoscopic or histologic) at surveillance colonoscopy (SC).ResultsBetween July 2008 and August 2019, 100 ARJ-LSLs and 313 rectal LSLs underwent EMR. ARJ-LSL median size was 40 mm (IQR 35–60 mm). Median follow-up at SC4 was 54 months (IQR 33–83 months). Technical success was 98%. Cancer was present in three (3%). Recurrence occurred in 15.4%, 6.8%, 3.7% and 0% at SC1–SC4, respectively. Among 30 ARJ-LSLs that received margin thermal ablation, no recurrence was identified at SC1 (0.0% vs 25.0%, p=0.002). Technical success, recurrence and adverse events were not different between groups, except for DMI (ARJ-LSLs 0% vs rectal LSLs 4.5%, p=0.027).ConclusionEMR is an effective technique for ARJ-LSLs and should be considered a first-line resection modality for the majority of these lesions.

Rectal bleeding caused by a syphilitic inflammatory mass

A 47-year-old man presented with fatigue, decrease appetite, abdominal pain and rectal bleeding. His colonoscopy revealed a single, firm, raised, centrally ulcerated mass at the anorectal junction. During this same admission, he was diagnosed with HIV and syphilis, found to have multiple hepatic lesions and positive cerebrospinal fluidvenereal disease research laboratory test (VDRL). Biopsies from both the hepatic lesions and rectal ulcer showed spirochaetes by immunostaining. The initial presentation was felt to be secondary to a rectal inflammatory mass caused by syphilis.