The Outcome of Local Excision of Rectal Adenomas with High-Grade Dysplasia by Transanal Endoscopic Microsurgery: A Single-Center Experience

Background: Local excision by transanal endoscopic microsurgery (TEM) is considered an acceptable treatment for rectal adenomas with high-grade dysplasia (HGD). This study aims to assess the likelihood of harboring an invasive carcinoma in preoperatively diagnosed HGD polyps and evaluate the risk factors for tumor recurrence in patients with final HGD pathology. Methods: Data from patients who underwent TEM procedures for adenomatous lesions with HGD from 2005 to 2018 at the Rabin Medical Center, Hasharon Hospital, were analyzed. Collected data included patient demographics, preoperative workup, tumor characteristics and postoperative results. Follow-up data including recurrence assessment and further treatments were reviewed. The analysis included two subsets: preoperative pathology of HGD (sub-group 1) and postoperative final pathology of HGD (sub-group 2) patients. Results: Forty-five patients were included in the study. Thirty-six patients had a preoperative diagnosis of HGD, with thirteen (36%) showing postoperative invasive carcinoma. Thirty-two patients had a final pathology of HGD, and three (9.4%) experienced tumor recurrence. Large tumor size (>5 cm) was significantly associated with recurrence (p = 0.03). Conclusions: HGD rectal polyps are associated with a significant risk of invasive cancer. Tumor size was a significant factor in predicting tumor recurrence in patients with postoperative HGD pathology. The TEM procedure is an effective first-line treatment for such lesions.

CLASSICA: Validating artificial intelligence in classifying cancer in real time during surgery

AIM

Treatment pathways for significant rectal polyps differ depending on the underlying pathology, but pre-excision profiling is imperfect. It has been demonstrated that differences in fluorescence perfusion signals following injection of indocyanine green (ICG) can be analysed mathematically and, with the assistance of artificial intelligence (AI), used to classify tumours endoscopically as benign or malignant. This study aims to validate this method of characterization across multiple clinical sites regarding its generalizability, usability and accuracy while developing clinical-grade software to enable it to become a useful method.

METHODS

The CLASSICA study is a prospective, unblinded multicentre European observational study aimed to validate the use of AI analysis of ICG fluorescence for intra-operative tissue characterization. Six hundred patients undergoing transanal endoscopic evaluation of significant rectal polyps and tumours will be enrolled in at least five clinical sites across the European Union over a 4-year period. Video recordings will be analysed regarding dynamic fluorescence patterns centrally as software is developed to enable analysis with automatic classification to happen locally. AI-based classification and subsequently guided intervention will be compared with the current standard of care including biopsies, final specimen pathology and patient outcomes.

DISCUSSION

CLASSICA will validate the use of AI in the analysis of ICG fluorescence for the purposes of classifying significant rectal polyps and tumours endoscopically. Follow-on studies will compare AI-guided targeted biopsy or, indeed, AI characterization alone with traditional biopsy and AI-guided local excision versus traditional excision with regard to marginal clearance and recurrence.

A Benign Rectal Polyp With Osseous Metaplasia: A Pediatric Case Report and Literature Review

Osseous metaplasia is rarely detected in benign and malignant lesions in the gastrointestinal tract, especially in the pediatric population under the age of six. Here, we report the case of a four-year-old boy with a history of constipation associated with painless bleeding per rectum for six months which was excised successfully. Microscopically, there was osseous metaplasia with no malignant changes. Further reporting is needed due to the limited cases of osseous metaplasia in colorectal polyps, with unknown mechanisms of pathogenesis and prognostic factors, specifically in the pediatric population.

Rectal Inflammatory Myoglandular Polyp with Osseous Metaplasia in a Child

Background: Inflammatory myoglandular polyp (IMGP) combines the histopathological features of juvenile polyp and Peutz-Jegher's polyp. Osseous metaplasia can be occasionally seen in various benign, adenomatous, and malignant polyps. Case report: A nine-year-old girl with hematochezia had a rectal polyp with histological features of IMGP with additional stromal osseous metaplasia. Conclusion: Benign osseous metaplasia can be found in IMGP.

Metastatic Prostate Cancer Presenting as a Rectal Polyp: A Rare Occurrence

The prostate is anatomically located anterior to the rectum. Due to this proximity, locally advanced tumors of the prostate can invade the rectal tissue; likewise, colorectal cancers can invade the prostate gland; This presents mainly as an invasive mass with an identifiable primary and is rarely an isolated lesion. Prostate cancer rarely affects the gastrointestinal tract. Few cases of prostate cancer metastatic to the gastrointestinal tract have been reported in patients with a known prostate cancer history. Initial diagnosis of prostate cancer diagnosed from a colonic polyp is rare. We report a case of metastatic prostate cancer first diagnosed from a rectal polyp. Our patient is a 76-year-old man who initially presented with fatigue and 20 pounds weight loss in five months. The patient never had a colonoscopy before the presentation. A colonoscopy was done, which showed multiple colonic polyps and a pathology report of metastatic prostate cancer from a 12 mm rectal polyp.

Enterobius vermicularis Infestation Mimicking Rectal Malignancy

Enterobius vermicularis is a common intestinal nematode of humans that can be considered relatively harmless. A polypoid lesion mimicking malignancy was detected in the rectum of a 66-year-old female patient who had been operated for sigmoid colon adenocarcinoma in the past. Histopathological examination of the lesion revealed no malignancy but there was adult E. vermicularis nematodes and eggs. In this case report, we aimed to present an enterobiasis infestation that produces non-necrotizing granuloma tissue in the rectum.

To do or not to do: prolapsed, bleeding, rectal polyp, a dilemma in austere circumstances

Polyps are defined as abnormal growth of tissue from a mucosal surface. Rectal polyps are the most common (2%) cause of gastro-intestinal bleed in children below 10 years. In adults, a rectal polyp presenting as an emergency with irreducible prolapse and massive bleeding causing severe anemia is seldom seen. We present one such case in which surgery was performed under austere circumstances before any investigations, as a life saving measure.

Robotic transanal minimally invasive surgery - technical, oncological and patient outcomes from a single institution

AIM

Robotic transanal minimally invasive surgery (R-TAMIS) is gaining traction around the globe as an alternative to laparoscopic conventional TAMIS for local excision of benign and early malignant rectal lesions. The aim was to analyse patient and oncological outcomes of R-TAMIS for consecutive cases in a single centre.

METHODS

A prospective analysis of consecutive R-TAMIS procedures over a 12-month period was performed. Data were collated from hospital databases and theatre registers.

RESULTS

Eleven patients (six men, five women), mean age 69.81 years (51-92 years), underwent R-TAMIS over 12 months utilizing a da Vinci Xi platform. The mean lesion size was 36 mm (20-60 mm) with a mean distance from the anal verge of 7.5 cm (3-14 cm). Five lesions were posterior in anatomical location, four anterior, one right lateral and one left lateral. All procedures were performed in the lithotomy position using a GelPOINT Path Platform. Mean operative time was 64 min (40-100 min). Complete resection was achieved in 10/11 patients with two patients being upgraded to a diagnosis of adenocarcinoma. Nine patients were diagnosed with dysplastic lesions. Four patients had a false positive diagnosis of an invasive tumour on MRI. Six patients required suturing for full-thickness resections. One patient had a postoperative bleed requiring repeat endoscopy and clipping. One patient (full-thickness resection of T3 tumour) proceeded to a formal resection without difficulty with no residual disease (T0N0, 0/22). One patient with a fully resected T2 tumour is undergoing a surveillance protocol. The mean length of stay was 1 day with two patients having a length of stay of 2 days and one patient of 4 days.

CONCLUSION

R-TAMIS could potentially represent a safe novel approach for local resection of rectal lesions.

Osseous Metaplasia in Rectal Polyp: A Case Report with Review of Probable Pathogenesis

Heterotopic bone formation is a rare event in gastrointestinal lesions, especially in the pediatric population. Osseous metaplasia is exceedingly rare in colonic polyps. We present a case of rectal juvenile polyp with stromal osseous metaplasia in a 10-year-old male child. This histologic finding is very rare in children with colorectal polyps.

Submucosal dissection has advantages over full-thickness transanal endoscopic microsurgery in selected rectal lesions

BACKGROUND

To establish the incidence of unsuspected malignancy in lesions excised through transanal endoscopic microsurgery (TEM) and examine the justification for full-thickness excision of all lesions thought to be benign pre-operatively.

METHODS

Demographic, operative and pathology data of all patients undergoing TEM at a single institution were collected in a prospectively maintained database. Follow-up data were collected with a focus on polyp recurrence rates and outcome in patients found to harbour malignancy. For lesions thought to be benign pre-operatively, a submucosal excision was routinely performed.

RESULTS

TEM was attempted in 156 cases between June 1999 and April 2013. Mean (standard deviation) patient age was 66.8 (2.1) years, with 111 males. Mean tumour size was 4.1 (1.6) cm, and mean height from anal verge was 10.4 (2.1) cm. In nine cases, the procedure was unable to be completed and in eight cases a deliberate full-thickness excision was performed. In 139 patients with a presumed benign lesion, mean operating time was 53.4 min. A total of 17 (12.2%) were found to harbour an unsuspected malignancy. Recurrent polyp was seen in 14 (11.7%) of 122 cases of benign pathology (mean follow-up 24.5 months) and was managed by endoscopic means in 10 patients. Mean length of stay was 1.2 days and complications occurred in 7% of cases. No patient with an unsuspected malignancy has developed recurrent disease (mean follow-up 43 months).

CONCLUSION

Submucosal TEM can result in low complication rates, short duration of surgery, short hospital stay and satisfactory recurrence rates when performed for presumed benign rectal tumours.

Transanal Approach to Rectal Polyps and Cancer

A transanal approach to rectal polyp and cancer excision is often an appropriate alternative to conventional rectal resection, and has a lower associated morbidity. There has been a steady evolution in the techniques of transanal surgery over the past 30 years. It started with traditional transanal excision and was revolutionized by introduction of transanal endoscopic microsurgery in early 1980s. Introduction of transanal minimally invasive surgery made it more accessible to surgeons around the world. Now robotic platforms are being tried in certain institutions. Concerns have been raised about recurrence rates of cancers with transanal approach and success of subsequent salvage operations.

Postirradiation Leiomyosarcoma of Rectum Presenting as a Polyp: Case Report and Review of the Literature

Radiation-induced leiomyosarcomas of the gastrointestinal tract are rare. Very few cases have been documented to date. The histological similarity to gastrointestinal stromal tumor has raised doubts if many of the cases originally reported to be leiomyosarcoma before the widespread use of CD117 were indeed gastrointestinal stromal tumors. We present a case of post-irradiation leiomyosarcoma presenting as a rectal polyp and review the literature.