P-OGC94 Outcomes of oesophagectomy post endoscopic mucosal resection

Background Within developed nations, oesophageal adenocarcinoma has the greatest incidence of any solid organ tumour with number escalating on a yearly basis. A recent expert review by the AGA suggests that high grade Barrett’s dysplasia and intramucosal adenocarcinoma are better treated endoscopically rather than oesophagectomy and that endoscopic management is a reasonable alternative to oesophagectomy for selected patients with low risk pT1b tumours.. Risk factors for nodal involvement and recurrence have been suggested by Lee et al (1). This study aims to review the pathological and clinical outcomes following oesophagectomy post EMR. Methods Results Conclusions Whilst some low risk patients had residual tumour at oesophagectomy, these findings were similar to Nelson et al 3; recurrent/recurrent local tumour could be potentially managed by repeat EMR. The absence of nodal metastasis in this small series is consistent with the AGA recommendation of EMR as a reasonable alternative to oesophagectomy for patients with selected low risk pT1b tumors.

Advanced Colon Cancer after Curative Resection of Intramucosal Adenocarcinoma with Endoscopic Submucosal Dissection

Endoscopic resection, particularly endoscopic submucosal dissection (ESD), for colorectal cancers enables a precise pathological diagnosis and safe R0 resection. The recurrence rate after ESD is generally extremely low, with annual surveillance colonoscopy recommended. However, surveillance may not be considered for super-elderly patients owing to their condition. This is a case report of an 85-year-old man in whom curative resection was achieved for an intramucosal adenocarcinoma with ESD. The patient presented with a hypoechoic mass located in his lower right abdomen, diagnosed via surveillance abdominal ultrasound. He had undergone curative ESD for intramucosal cecal cancer 2 years prior. Colonoscopy revealed a type 2 epithelial tumor at the proximal aspect of the ESD scar. Ileocolic resection with lymph node dissection was performed. An epithelial tumor and well-differentiated adenocarcinoma but not a submucosal tumor was detected in the mucosal layer. The lesion was diagnosed not as a local recurrence after ESD but as a newly emerged original advanced cancer. After ESD for colorectal cancer, a newly developed advanced cancer may occur at the site of the ESD scar in a shorter term than usual. Surveillance colonoscopy after ESD is necessary even for super-elderly patients.

Intramucosal duodenal adenocarcinoma concomitant with Saint’s triad

Duodenal tubulovillous adenomas are rare and have malignant potential. Their successful management depends on the preoperative diagnosis and adequate excision. Endoscopic mucosal resection or submucosal dissection can control superficial tumors. Adenocarcinoma of the duodenum may originate in tubular or tubulovillous adenoma, and possible diagnostic challenges occur concerning the endoscopic biopsy findings. We report a 62-year-old female with chronic epigastric burning and a bolus sensation. Upper gastrointestinal endoscopy showed a non-ampullary duodenal tumor, and the biopsy study diagnosed a tubulovillous adenoma. Further mucosectomy revealed an intramucosal adenocarcinoma in a tubulovillous adenoma with a tumor-free pedicle. Besides the intestinal neoplasms, the patient had the diagnosis of classical Saint’s triad; and the manifestations were hiatus hernia, gallbladder disorder, and colonic diverticula. The objective is to report two scarcely described conditions and comment on controversial points of view about the concomitance of Saint’s triad and malignancy. Case reports can reduce late diagnosis, enhancing the suspicion index on rare diseases.

Radiofrequency ablation for intraductal extension of ampullary adenomatous lesions: proposal for a standardized protocol

Background and study aims Intraductal extension of ampullary adenoma represents a challenging endoscopic issue. Intraductal radiofrequency ablation (RFA) has been recently suggested, but evidence and standardization of this technique are still lacking. This study aimed to provide a long-term evaluation of clinical efficacy and safety of intraductal RFA ablation with a standardized algorithm of treatment. Patients and methods Data were prospectively collected from consecutive patients with intraductal extension of adenomatous ampullary lesions from January 2016 to November 2018. Endpoints of the study were clinical success evaluated on histology results at the last follow-up, technical success, and adverse events assessment. Results Nine patients with intraductal (biliary ± pancreatic) extension of ampullary adenomas were treated with RFA during the study period. Histology on the papillectomy specimen confirmed intraductal involvement with low-grade dysplasia (LGD) in five cases (56 %), high-grade dysplasia (HGD) in three (33 %), and HGD with intramucosal adenocarcinoma in one patient (11 %). Additional argon plasma coagulation to ablate the adenoma on the duodenal mucosa was applied in five patients (56 %). Technical success was 100 %. One patient (11 %) with failed pancreatic stenting, developing acute pancreatitis after RFA, recovered with medical therapy. After a median follow-up of 21 months (IQR 20–31), six patients (67 %) achieved clinical success being free of recurrence, whereas one was diagnosed with persistence of adenocarcinoma, one with recurrent HGD, and one with recurrent LGD. Conclusions In our experience, intraductal RFA achieved acceptable results after a 2-year follow-up. Further studies are required to confirm our results and to select those patients most likely to respond.

Invasive carcinoma versus pseudoinvasion: interobserver variability in the assessment of left-sided colorectal polypectomies

ObjectivesMisplaced epithelium in adenomas can occasionally be difficult to distinguish from invasive adenocarcinoma. We evaluated interobserver variability in the assessment of left-sided colon polypectomies for pseudoinvasion versus invasive adenocarcinoma and further investigated relevant histological findings.Methods28 consecutive left-sided colon polyps with the keywords “pseudoinvasion”, “epithelial misplacement”, “herniation”, “prolapse” or “invasive adenocarcinoma” were collected from 28 patients and reviewed by eight gastrointestinal pathologists. Participants assessed stromal hemosiderin, lamina propria/eosinophils surrounding glands, desmoplasia, high grade dysplasia/intramucosal adenocarcinoma and margin status and rendered a diagnosis of pseudoinvasion, invasive adenocarcinoma, or both.ResultsAgreement among pathologists was substantial for desmoplasia (κ=0.70), high grade dysplasia/intramucosal adenocarcinoma (κ=0.66), invasive adenocarcinoma (κ=0.63) and adenocarcinoma at the margin (κ=0.65). There was moderate agreement for hemosiderin in stroma (κ=0.53) and prolapse/pseudoinvasion (κ=0.50). Agreement was low for lamina propria/eosinophils around glands (κ=0.12). For invasive adenocarcinoma, seven or more pathologists agreed in 24 of 28 cases (86%), and there was perfect agreement in 19/28 cases (68%). For pseudoinvasion, seven or more pathologists agreed in 19 of 28 cases (68%), and there was perfect agreement in 16/28 cases (57%).ConclusionModerate to substantial, though imperfect, agreement was achieved in the distinction of pseudoinvasion from invasive carcinoma.

A133 GASTRIC ESD: PRELIMINARY EXPERIENCE IN A TERTIARY CENTER IN QUEBEC

Background Endoscopic submucosal dissection (ESD) is an endoscopic procedure developed in Asian countries to treat early gastric cancer (EGC). Western countries have less experience with this challenging technique. Aims The goal of this study is to evaluate the effectiveness of ESD as a preliminary experience. Methods This is an unicentric retrospective study of all consecutive gastric ESD for adenomas or EGC from 07/2017 to 08/2020. The primary endpoints were en bloc and R0 resection rates. Results Nineteen patients (mean age 74.2 (54–88), sex ratio 3F/16M) and 23 lesions were included. Mean diameter was 25 mm (10–90). Treatment was previously performed in 7 cases (30.4%), by ESD (5) or EMR (2). The procedure, performed under general anaesthesia, lasted on average 148 minutes (45–412). En bloc resections were performed in 16 cases (69.6%); 5 cases (21.7%) were converted to P-EMR and there was a failure to resect the lesion because of deep invasion or perforation in 2 cases (8.7%). Pathologic examination demonstrated 2 low-grade dysplasia, 4 high-grade dysplasia and 15 adenocarcinomas: intramucosal (8), sm1 (2), sm2 (2), sm3 (1) or sm deep (2). R0 and curative resection rates were 43.5% and 39.1% respectively. The complication rate related to the procedure was 30.4% including 5 perforations and 2 delayed bleeding: all were managed endoscopically. Five patients (21.7%) underwent subsequent gastrectomy for non-curative resection (4) or failed resection (1); 3 had no residual disease on final pathology, 1 had high grade dysplasia and 1 had intramucosal adenocarcinoma. One patient went to palliative care because he was unfit for surgery. Follow-up endoscopy was completed in all 17 patients who underwent endoscopic resection (mean 10 months (2–24)). Recurrence occurred in 23.5% (4/17); all were successfully treated by another ESD. Conclusions In our preliminary experience, the rate of en bloc and R0 resection were 70% and 44%. Compared to other studies, these low en bloc and curative resection rates may be explained by technically difficult lesions during the learning curve and might improve with experience. Nevertheless, surgery has been avoided in 13/19 patients (68%) with endoscopic intervention. Funding Agencies None

Alpha-Fetoprotein-Producing Early Gastric Cancer with Intramucosal Hepatoid and Fetal Enteric Differentiation

Alpha-fetoprotein (AFP)-producing gastric carcinomas (AFPGCs) are relatively rare tumors known to have a poor prognosis and commonly found as advanced lesions. Histologically, AFPGCs have been described as having hepatoid and fetal enteric (enteroblastic) morphology and are associated with conventional adenocarcinomas. Prior studies reported a hepatoid component present only in invasive areas and hypothesized that AFPGCs may develop hepatoid features during the process of tumor invasion. We report three cases of AFP-producing early gastric cancer which had an intramucosal hepatoid component. Immunohistochemistry showed that the hepatoid component was diffusely immunoreactive for SALL4, AFP, arginase-1, and HepPar1, and focally for CDX2 and PDX1. An intramucosal transition between the hepatoid component and conventional intramucosal adenocarcinoma was identified. Two patients also had a coexistent fetal enteric component, which was admixed with a hepatoid component. Although at an early stage one patient subsequently developed liver metastasis and a second patient was suspected of having liver metastasis, these were not biopsy-proven. The latter patient had a previous history of hepatocellular carcinoma (HCC) and SALL4 was used on the HCC to distinguish metastatic/further HCC from a gastric metastatic primary with hepatoid differentiation.