Muscularis Propria Involvement Research Articles

Gastric Glomus Tumor Resected by Submucosal Tunneling Endoscopic Resection

ABSTRACT Gastric glomus tumor (GGT) is a rare mesenchymal neoplasm, that is usually asymptomatic. Although benign, malignant transformation has been reported. A 59-year-old man presented with dyspepsia refractory to treatment with proton-pump inhibitor over 6 months. Esophagogastroduodenoscopy revealed a 30 mm subepithelial lesion in the distal gastric antrum, in contact with the pylorus, but biopsies were nonspecific. Upper endoscopic ultrasound revealed a well-defined submucosal echogenic lesion measuring 30 × 20 mm, without muscularis propria involvement. A fine-needle aspiration biopsy showed GGT features. En bloc endoscopic resection was performed using the submucosal tunneling endoscopic resection technique. The histopathological study of the specimen confirmed the diagnosis of a GGT with free margins. The patient remains symptom-free after a 9-month follow-up. We highlight the rare diagnosis of GGT and the possibility of curative en bloc endoscopic resection with submucosal tunneling endoscopic resection.

A subepithelial lesion algorithm for endoscopic (SAFE) resection in the upper gastrointestinal tract.

Complete excision of upper gastrointestinal subepithelial lesions (U-SELs) eliminates diagnostic uncertainty, obviates the need for surveillance, and may be necessary for definitive diagnosis and management. Current guidelines lack precision and cohesion, and surgery is associated with significant morbidity. We describe and report on the outcomes of our SEL algorithm for endoscopic (SAFE) resection. U-SELs were enrolled prospectively over 115 months until March 2023. All subjects underwent axial (computed tomography) imaging and endoscopic ultrasonography (EUS) to exclude a large exophytic component or invasion into local structures, and assess for muscularis propria (MP) involvement. 106 U-SELs (41 esophageal, 65 gastric) were resected (mean patient age 60.6 [SD 13.4]; 51.9% male). Esophageal U-SELs underwent endoscopic submucosal dissection (ESD; n = 22) or submucosal tunneling endoscopic resection (STER) if MP involvement was suspected (n = 19). Gastric U-SELs underwent STER (n = 6 at cardia), ESD (n = 47), or exposing endoscopic full-thickness resection (e-EFTR; n = 12). Technical success rates were 97.6% and 92.3%, respectively. Among the noncardiac gastric U-SELs, five resections (9.6%) were completed laparoscopically owing to deep and broad full-thickness involvement; five (9.6%) required laparoscopic gastrotomy and surgical retrieval after successful resection and closure owing to a large lesion size (mean 47 mm). There was no delayed bleeding, perforation, or recurrence at 13 months. U-SELs may be effectively and safely treated by endoscopic resection. The SAFE approach provides a framework that facilitates structured decision-making. Esophageal U-SELs suspected of involving the MP should undergo STER. Gastric SELs are best managed by ESD, with a view to proceeding to e-EFTR. A laparoscopic upper gastrointestinal surgeon should be available in case surgical retrieval of the specimen or laparoscopic completion is required.

Commentary.

The immersion into the submucosal layer with endoscopic submucosal dissection two decades ago led us to a new era of third-space endoscopy and endoscopic full-thickness resection, whereby many lesions, even with full-thickness muscularis propria involvement, can be safely removed endoscopically. Therefore, endoscopic recognition, characterization, and management of iatrogenic full-thickness mural defects is critical to ensure technical success and safety [1] [2]. The focus has now been increasingly shifting towards developing new devices to close progressively larger defects throughout the gastrointestinal tract. These closure tools, including through-the-scope (TTS) clipping, suture-based, or endoscopic vacuum therapy, need to be adapted to the size and location of the defects. In an experimental study [3] and in this video, Zhang et al. showed the efficacy of novel TTS twin clips (TTS-TCs) for closing wounds ≥ 25 mm, when intertwined with traditional TTS clips, functioning as coadjuvants in reducing submucosal dead space and achieving a firm closure effect. In summary, the TTS-TC holds great promise as a definitive mural closure device as it can be used in a deflated lumen, in situations where access is poor, and promptly without the need for endoscope exchange or reinsertion. Further prospective comparative studies are required to establish efficacy, safety, and cost–effectiveness.

Metastasis Prevalence and Survival of Patients with T1-2 Gastric Neuroendocrine Tumor Treated with Endoscopic Therapy and Surgery.

The selection criteria and long-term outcomes of endoscopic therapy (ET) for gastric neuroendocrine tumors (G-NETs) remain controversial. Using Surveillance, Epidemiology, and End Results (SEER) Program database, we assessed the prevalence of metastasis of early G-NETs and long-term outcomes of ET in G-NET patients with good/moderate differentiation and no muscularis propria (MP) involvement. A total of 2207 patients with stage T1 and T2 G-NETs were included. The depth of invasion into MP [odds ratio (OR) 4.581, 95% confidence interval (CI) 2.571-8.162; P < 0.001] and size of > 20mm (OR 5.656, 95% CI 2.002-15.975; P = 0.001) were significantly associated with metastasis. The 5-year overall survival (OS) and cancer-specific survival (CSS) of the ET group were similar to the surgery group (91.11% vs. 91.09%, P = 0.750; 99.26% vs. 99.01%, P = 0.173). In the multivariable Cox proportional hazards regression models adjusting for age, gender, race, year of diagnosis, SEER region, depth of tumor invasion, site of cancer, tumor size, and chemotherapy, procedures employed (ET or surgery) had no significant impact on the OS [hazard ratio (HR) 1.189; 95%CI 0.721-1.961; P = 0.498] and CSS (HR 0.684; 95% CI 0.021-22.727; P = 0.832). The long-term outcome of survival did not appear to differ between ET and surgery in G-NETs with good/moderate differentiation, ≤ 20mm size, and no MP involvement.

Prognostic value of subclassification of pT2 stage in patients with gastric cancer.

e16070 Background: The data about prognosis difference of patients with pT2 stage gastric cancer (GC) after radical surgery is diverse. The latest TNM staging system does not define details for the pT2 stage subclassification. The purpose of this study is to investigate the survival difference according to depth of tumor muscularis propria involvement and find biomarker to reinforce the prognostic and therapy-guided ability of TNM staging system. Methods: A total of 380 patients with pT2 GC after radical surgery were retrospectively analyzed, including 185 in sMP (superficial muscularis propria) group and 195 in dMP (deep muscularis propria) group. The log-rank test was used to identify survival outcomes. Independent factors were identified by multivariable Cox proportional hazard model for OS. Results: The overall survival (OS) of patients in sMP group was significantly better than patients in dMP group (P = 0.007). On multivariate analysis, age (＜60 vs ≥60: P = 0.004, HR, 2.075(95%CI: 1.261-3.414)), primary location (P = 0.002, U vs M: 0.985(0.509-1.909); U vs L: 0.400(0.235-0.680)), depth of tumor invasion (sMP vs dMP: P = 0.050, 1.584(1.261-3.414), pN stage (P = 0.000, N0 vs N1: 2.304(1.364-3.890); N0 vs N2: 1.879(0.967-3.652); N0 vs N3: 5.335(2.533-11.237)), expression of p53 (negative vs positive: P = 0.016, 1.793(1.117-2.879)) were independent prognostic factors for the OS. In pN0 stage tumor, the sMP group had a significantly better OS than the dMP group (P = 0.014). When classified as N+, there was no obviously difference of OS between two groups (P = 0.384). When patients were stratified according to the depth of tumor invasion and pN stage, the OS was not significant difference between dMPN0 group and sMPN1-2 group (P = 0.100), the OS of patients with adjuvant chemotherapy were statistically better than those without in dMPN0 group (P = 0.045), but not significance in sMPN1-2 group (P = 0.486). After further grouping according to adjuvant chemotherapy status, in comparison to sMPN1-2 patients, dMPN0 patients with adjuvant chemotherapy had better OS (P = 0.015), but not significance in patients without (P = 0.599). Upon stratification according to the expression of p53, in p53-positive group, greater OS could be observed in patients with sMPN0 than patients with dMPN0 (P = 0.002). Similar OS could be seen between dMPN0 patients with p53-positive and T2N1-2 patients (P = 0.872). Conclusions: For pT2 gastric cancer patients, there were differences in survival outcomes for sMP and dMP invasion. The prognosis of dMPN0 patients were similar to patients with sMPN1-2, and dMPN0 patients who accepted adjuvant chemotherapy had an improved prognosis than those without. Appropriate adjuvant chemotherapy should be considered for patients with dMPN0 stage. In addition, positive expression of p53 could be potential factors to identify the different prognoses for patients with pT2 gastric cancers.

Diagnosis and Management of Rectal Neuroendocrine Tumors (NETs)

Rectal neuroendocrine tumors (NETs) are rare, with an incidence of 0.17%, but they represent 12% to 27% of all NETs and 20% of gastrointestinal NETs. Although rectal NETs are uncommon tumors, their incidence has increased over the past few years, and this is probably due to the improvement in detection rates made by advanced endoscopic procedures. The biological behavior of rectal NETs may be different: factors predicting the risk of metastases have been identified, such as size and grade of differentiation. The tendency for metastatic diffusion generally depends on the tumor size, muscular and lymphovascular infiltration, and histopathological differentiation. According to the current European Neuroendocrine Tumor Society (ENETS) guidelines, tumors that are smaller than 10 mm and well differentiated are thought to have a low risk of lymphovascular invasion, and they should be completely removed endoscopically. Rectal NETs larger than 20 mm have a higher risk of involvement of muscularis propria and high metastatic risk and are candidates for surgical resection. There is controversy over rectal NETs of intermediate size, 10–19 mm, where the metastatic risk is considered to be 10–15%: assessment of tumors endoscopically and by endoanal ultrasound should guide treatment in these cases towards endoscopic, transanal, or surgical resection.

Factors predicting poor survival in early gastric cancer: A SEER analysis.

e15548 Background: The benefit of adjuvant treatment in gastric adenocarcinoma patients with muscularis propria involvement but not beyond is unclear. We aim to establish a model that identifies the factors that could adversely affect the prognosis in these patients, whom could potentially benefit from adjuvant treatment. Methods: We used the Surveillance, Epidemiology, and End Results Program (SEER) database to identify subjects with stage T2aN0M0 gastric adenocarcinoma according to the 6th AJCC TNM staging system who underwent tumor resection between 2004-2015. The effect of the following factors on the 5-year overall survival (OS) was evaluated using Kaplan-Meier analysis: demographics, tumor size, grade and site, number of lymph nodes (LNs) being examined and extent of surgery. Factors with a P value &lt; 0.1% in log-rank test were entered in a Cox proportional hazard ratio (HR) model. Results: We identified 1337 patients who met the inclusion criteria. After a median follow-up of 42 months (1-60), the 5-year OS was 64% with the median being unreached. The following factors were significantly associated with shorter OS in univariate analysis: Age &gt; 60 years with a HR = 1.86 (95% CI 1.49-2.32), Non-Hispanics excluding non-Hispanic Asian and Pacific Islanders with a HR = 1.87 (95% CI 1.54-2.28), patients with less than 15 lymph nodes examined at the time of surgery with a HR = 1.86 (95% CI 1.52-2.26), tumors at the fundus and cardia of the stomach compared to other sites with a HR = 1.73 (95% CI 1.37-2.15), those who underwent endoscopic resection with a HR = 2.27 (95% CI 1.16-4.4) and those who didn’t receive chemotherapy with a HR = 1.23 (95%CI 1.001-1.52) . On multivariate analysis; the following factors were predictors for worse OS; Age &gt; 60 years with a HR = 1.97 (95% CI 1.46-2.65), Non-Hispanics excluding non-Hispanic Asian and Pacific Islanders with a HR = 1.45 (95%CI 1.10-2.00), those in whom less &lt; 15 LNs were examined at the time of surgery with a HR = 1.75 (95% 1.38-2.22) and gastric adenocarcinoma at the cardia and fundus with a HR = 1.50 (95%CI 1.20-1.86). Conclusions: Patients with T2aN0M0 gastric adenocarcinoma, and one of the adverse prognostic factors in our Cox-proportional hazard ratio model need to be studied for possible benefit of adjuvant treatment.

High-frequency miniprobe endoscopic ultrasonography in the management of benign esophageal strictures.

Background:Endoscopic ultrasonography (EUS) can predict the response to endoscopic dilatation by delineating the extent of esophageal wall involvement in benign strictures. In contrast to conventional echoendoscopes, the EUS miniprobe can be negotiated across the stricture and thus provide more information. This study retrospectively evaluated the role of miniprobe EUS in predicting the response to endoscopic dilatation in benign esophageal strictures.Methods:We analyzed the records of 24 patients (mean age: 48.1±17.9 years) with benign esophageal strictures (corrosive 11, peptic 5, post-radiation 3, anastomotic 2, and others 3) who underwent miniprobe EUS prior to endoscopic dilatation.Results:The stricture was located in the upper, middle and lower esophagus in 2, 9 and 13 patients, respectively. The mean length of the stricture was 3.4±1.9 cm. Miniprobe EUS was able to examine the stricture completely in all patients. The mucosa was involved in 6, mucosa and submucosa in 4, and mucosa, submucosa and muscularis propria in 14 patients. The mean maximum wall thickness of esophageal wall on EUS at the level of the stricture was 8.2±2.8 mm. The mean number of sessions required to achieve adequate dilation was 4.7±2.6. Patients with mucosal involvement required significantly fewer endoscopic sessions for adequate dilatation as compared to patients with muscularis propria involvement (1.8 vs. 6.2 sessions, respectively; P=0.0002). Patients with greater esophageal wall thickness required more endoscopic sessions (r=0.737) (P=0.00004).Conclusion:Miniprobe EUS, by delineating the extent of wall involvement as well as measuring wall thickness in benign esophageal strictures, can predict the response to endoscopic dilatation.

Gall Bladder Cancer - Is the Stage Set? Yet!

The current TNM staging of gall bladder cancer (GBC) has some shortcomings. We propose some changes in the current TNM staging of GBC. We propose that involvement of muscularis propria should be classified as T2 (instead of current T1b) and stage grouped as II (instead of current I). T4 in GBC should be subdivided into T4a (perforation of serosa, involvement of omentum, CBD, stomach/duodenum and colon) and T4b (involvement of pancreas, hepatic artery and portal vein). Hepato-duodenal ligament lymph nodes alone should be classified as N1; periduodenal, peripancreatic and common hepatic artery lymph nodes should be classified as N2 and stage grouped as IVA; non-regional (distant) lymph nodes should be classified as M1a and distant (non-nodal) metastases should be classified as M1b. We also propose changes in the TNM stage grouping of GBC – stage I (T1 N0 M0), II (T2 N0 M0), III (T3 N0 M0, T1-3 N1 M0) and IV (T4 Any N M0, Any T N2 M0, Any T Any N M1). Tumors at GB neck are difficult to resect and have poorer prognosis even after resection. Surgical obstructive jaundice (SOJ) in GBC makes resection difficult and is associated with poorer prognosis even after resection. We also propose inclusion of non TNM factors viz. site of tumor (fundus/body or neck) and SOJ in staging of GBC.

Clinicopathological study of 9 cases of prostate cancer involving the rectal wall

BackgroundProstate cancer involving the rectal wall is rare and may lead to diagnostic pitfalls.Case presentationOut of 9504 patients with rectal tumors between January 2003 and January 2015, 9 patients (elderly with a mean age of 74 years) with prostate cancer involving the rectal wall were clinically misdiagnosed with rectal cancer. The lesions were located in the rectum, and included 3 circumferential rectal masses, 1 ulceration lesion, 1 crater-like mass, and 4 protruding lesions. Specimens were acquired using biopsy, fine needle aspiration, or resection. The initial symptoms of these patients included rectal urgency, bowel obstruction, and lower gastrointestinal bleeding. Prostate-related symptoms were not obvious. Histologically, 2 cases showed cancer cell invasion in the mucosa, 1 showed transmural invasion from the mucosa to subserosal soft tissues, and 7 cases had submucosa and muscularis propria involvement. All the 9 cases had muscularis propria involvement. However, there were no intraepithelial neoplasias in the mucosal layer, which is reminiscent of rectal carcinoma. The tumors consisted of small-sized or foamy cells that formed acinus-like, duct-like, and cribriform-like structures. We conducted histological staining and an immunohistochemical analysis for CDX-2, prostate-specific antigen (PSA), P504s, villin, carcinoembryonic antigen, CK-pan, cytokeratin 20, and Ki-67. All tumors were PSA and CK-pan positive, 5 of 9 tumors were P504s-positive, and all tumors were negative for the other markers. All patients underwent standard therapy for prostate cancer after the definitive pathological diagnosis. As of March 31, 2015, 8 patients were alive and 1 had died of prostate cancer 6 months posttreatment.ConclusionsAdenocarcinoma appearing in the rectal wall is not always rectal carcinoma. It is necessary to perform a differential diagnosis for prostate cancer in cases of rectal malignant tumors in elderly male patients. Any treatment should be postponed until the final definitive diagnosis is reached.

Clinicopathologic Characteristics and Mutational Status of Succinate Dehydrogenase Genes in Paraganglioma of the Urinary Bladder: A Multi-Institutional Korean Study.

- Because of the limited number of available primary bladder paraganglioma (PBPG) cases, the rates of succinate dehydrogenase (SDH) mutations and the clinicopathologic characteristics of SDH-deficient tumors have not been fully studied. - To define the clinicopathologic and molecular characteristics of PBPGs. - A total of 52 PBPGs were collected retrospectively. SDHA and SDHB immunohistochemical stains were performed. In cases of SDHB expression loss, mutation analyses of SDHB, SDHC, and SDHD were performed. - The clinicopathologic features were analyzed for 52 cases (M:F = 27:25), with a mean age of 56 years (range, 22-79 years). Tumor sizes were 0.5 to 8 cm (mean, 2.4 cm). Tumor necrosis was present in 5 of 52 cases (10%), involvement of muscularis propria in 41 (79%), and lymphovascular tumor invasion in 6 (12%). During a mean follow-up period of 41 months (range, 1-161 months), 3 of 52 patients (6%) developed metastases, but no one died from the disease. Immunohistochemistry for SDHA and SDHB showed that all cases were SDHA intact. Among them, 43 cases had intact SDHB, whereas 9 cases were SDHB deficient. Compared with the SDHB-intact cases, the SDHB-deficient cases were characterized by large tumor sizes (4.5 versus 1.9 cm; P < .001), a higher number of mitoses per 10 high-powered fields (2.6 versus 0.1; P = .002), and frequent lymphovascular tumor invasion (33% versus 7%; P = .02) and metastases (22% versus 2%; P = .02). Mutational analyses for SDHB, SDHC, and SDHD were performed in 9 SDHB-deficient cases. Among them, 6 cases were successfully sequenced and revealed SDHB mutations only. - Large tumor size, a higher number of mitoses, and the presence of lymphovascular tumor invasion and SDHB mutations suggest malignant paraganglioma.

Primary tubulovillous adenoma of the urinary bladder: Case report and literature review

Primary tubulovillous adenomas are scarcely encountered in the urinary tract, and most of these tumors arise from the intestinal segments of urinary reconstruction. We report the extremely rare case of tubulovillous adenomas primarily occurring in the urinary bladder in this article. A 50-year-old female patient initially presented with painless gross hematuria for several times within 1 month. Image studies, including abdominal ultrasonography and computed tomography, demonstrated one urinary bladder tumor with suspicious perivesical invasion. The diagnosis was made by a transurethral resection and histopathology, and no involvement of muscularis propria was confirmed. Although the pathogenesis and clinical behavior are not well understood, tubulovillous adenomas may have a tendency to undergo malignant transformation into the form of invasive adenocarcinomas. Complete resection and rigorous follow-up are strongly recommended.

895 Endoscopic Mucosal Resection of Duodenal Carcinoid Tumors: A Single Tertiary Care Center Experience

Background and Aims: There is no consensus on the optimal treatment of duodenal carcinoid tumors. Endoscopic mucosalresection (EMR) is considered appropriate for tumors <1cm in size confined to the mucosa/submucosa. In this retrospective study we examine the safety and efficacy of duodenal carcinoid EMRat a single tertiary care center. Methods: All patients with duodenal carcinoids resected via EMR at Duke University Medical Center from 1999 to 2012 were identified. All had pathologic diagnoses and endoscopic ultrasound (EUS), followed by EMR using cap-ligation or standard snare polypectomy. Results: 43 duodenal carcinoids were resected in 40 patients. 91% of tumors were located in the bulb. All tumors were limited to the mucosa or submucosa. Mean tumor size was 7.0mm. 28 tumors were removed using cap-ligation and 15 using snare polypectomy. Two post-procedure GI bleeds and two perforations occurred (one managed endoscopically, one managed surgically). 17 (40%) resected tumors had positive margins. 13 cases were lost to follow-up. Of the other 27 patients, 3 went on to surgical resection (all had positive margins at EMR). Mean follow-up time was 28.3 months. Three patients had local recurrence (2/3 had positive margins on initial resection), and three had lymph node metastases (all had positive margins on initial resection). Conclusion: This is the largest single center study of its kind. Endoscopic resection of duodenal carcinoids should be considered prior to surgical resection after EUS evaluation to exclude muscularis propria involvement and lymph node spread. The significance of positive margins requires further study. Careful follow-up is necessary.

Endoscopic Mucosal Resection for Esophageal Granular Cell Tumors

Purpose: Granular cell tumors (GCTs) are rare subepithelial lesions that may arise in the esophagus. Endoscopic mucosal resection (EMR) is used for the diagnosis, staging, and eradication of superficial esophageal neoplasms. EMR has been suggested as a treatment option for GCTs, but data is limited. Methods: A prospectively-collected pathology database was used to identify patients with esophageal GCT over the past 10 years at a university medical center. Information regarding demographic data, procedural findings, technical details of resection and adverse events was collected. Results: Fifteen patients (11 female, 4 male) with a mean age of 40 years (range, 21-64 years) were diagnosed with esophageal GCT. The majority of lesions (93%) were located in the distal esophagus. EMR was not performed in 4 patients (2 with muscularis propria involvement by EUS, 1 due to physician/patient decision, 1 GCT could not be re-identified). EMR was attempted by an experienced therapeutic endoscopist in the remaining 11 patients (Table 1). En bloc resection was achieved in 10/11 patients (91%) requiring only one session. Ligation-assisted EMR was performed in 8 patients (73%) and cap-assisted EMR was performed in the remaining 3 patients. A submucosal lift with normal saline was used in 7 cases (64%). Multiple esophageal GCTs were noted in two patients (case #5 had 4 lesions & case #8 had 2 lesions), all of which were completely excised. One lesion demonstrated a satisfactory submucosal lift; however, it was too large to be suctioned into a cap and further attempts to salvage resection failed to fully engage the lesion within the snare. This same patient later underwent operative resection of a gastric submucosal lesion and was diagnosed with a gastric GCT. There were no adverse events associated with ligation-assisted EMR. Two patients (18%) experienced acute bleeding after cap-assisted EMR. The patient in case #9 was treated with 4 cc of epinephrine with hemostasis achieved. The patient in case #10 had an ulcerated lesion that was treated with 8 cc of epinephrine after resection. This patient and was admitted to the hospital for overnight observation without further intervention. There were no cases of perforation.Table: [1871]Conclusion: Esophageal GCTs occur more commonly in the distal esophagus and appear to have a female predilection. EMR has a high rate of complete en bloc resection for esophageal GCTs. Lesion size is a limitation to EMR. While ligation-assisted EMR may reduce the risk of immediate bleeding, endoscopists performing EMR of esophageal GCTs should be prepared to manage the complications of bleeding. Disclosure: Dr. Chandrasekhara - None. Dr. Wilson - None. Dr. Ginsberg - None. Dr. Kochman - Spouse works for Merck.

A precystectomy decision model to predict pathological upstaging and oncological outcomes in clinical stage T2 bladder cancer

To categorize patients with clinical stage T2 bladder cancer into risk groups based on their potential for pathological upstaging and eventual oncological outcomes at cystectomy. To pre-emptively identify such patients who will be upstaged and have poor outcomes after cystectomy, aiming to better determine the ideal candidates for neoadjuvant chemotherapy. A retrospective review was conducted of 1964 patients who underwent radical cystectomy for bladder cancer with intent to cure at the University of Southern California between 1971 and 2008. Neoadjuvant chemotherapy-naïve patients with clinically organ-confined urothelial carcinoma invading bladder muscle (cT2N0M0) were included. Univariate analysis and multivariable decision tree modelling with cross-validation were employed to identify precystectomy variables that could predict pathological upstaging and poor oncological outcomes. A total of 948 patients met the inclusion criteria, of whom 512 (54%) patients were upstaged at cystectomy; upstaging was associated with a worse recurrence-free and overall survival (both P < 0.001). Age, presence of hydronephrosis, evidence of deep muscularis propria invasion and lymphovascular invasion on transurethral resection specimen, as well as tumour growth pattern and count, were significantly associated with upstaging. When these factors were included in a decision tree model, 70.6% of patients with hydronephrosis experienced upstaging and had the worst outcome (P < 0.001). In patients without hydronephrosis, tumour growth pattern was a second-tier discriminator (P < 0.001); in patients with non-papillary tumours, 71.7% of cases with evidence of deep muscularis propria involvement experienced upstaging compared to 53.8% of cases with no deep muscle involvement (P = 0.012), whereas, among patients with combined papillary and non-papillary features, 33% of cases aged ≤65 years were upstaged compared to 47% of cases aged >65 years (P = 0.036). The cross-validated decision tree resulted in three risk groups with significantly varying probabilities of recurrence-free and overall survival (both with overall P < 0.001). Hydronephrosis, tumour growth pattern, deep muscle involvement and age can collectively identify patients with cT2N0M0 bladder cancer who have varying risks of pathological upstaging. Such categorization using a visually intuitive model can facilitate clinical decision-making with respect to neoadjuvant therapy in these patients.

Influencing factors related to lymphatic metastasis of T2 rectal carcinoma

To study the risk factors associated with lymphatic metastasis of T2 rectal carcinoma. A consecutive series of 122 patients with T2 rectal cancer who underwent radical surgery in the First Affiliated Hospital of Fujian Medical University from 2006 to 2011 were included for retrospective analysis. Risk factors associated with lymphatic metastasis were investigated. The rate of lymph node metastasis was 21.3% (26/122). Distance to anal verge(P<0.05), morphological type(P<0.05), histological type(P<0.05), tumor differentiation(P<0.05), and depth of invasion(P<0.05) were risk factors for lymph node metastasis in T2 rectal cancer by univariate analysis. The depth of invasion remained statistically significant by multivariate analysis. The rate of lymph node metastasis was 13%(7/54) in patients with shallow muscularis propria involvement, and 28%(19/68) in those with deep muscularis involvement. For T2 rectal cancer with shallow muscularis involvement, the risk of lymph node metastasis is low and transanal excision should be considered.

Succinate Dehydrogenase-Deficient GISTs

Most gastrointestinal stromal tumors (GISTs) are driven by KIT or PDGFRA-activating mutations, but a small subset is associated with loss of function of the succinate dehydrogenase (SDH) complex of mitochondrial inner membrane proteins. This occurs by germline mutations of the SDH subunit genes and hitherto unknown mechanisms. SDH-deficient GISTs especially include pediatric GISTs and those associated with Carney triad (CT) or Carney-Stratakis syndromes (CSSs); the latter 2 also include paraganglioma as a component. SDH-deficient GISTs were identified in this study on the basis of immunohistochemical loss of succinate dehydrogenase subunit B (SDHB), which signals functional loss of the SDH complex. We found 66 SDH-deficient GISTs among 756 gastric GISTs, with an estimated frequency of 7.5% of unselected cases. Nearly, all gastric GISTs in patients <20 years, and a substantial percentage of those in patients <40 years, but only rare GISTs in older adults were SDH deficient. There was a female predominance of over 2:1. Two patients each had either pulmonary chondroma or paraganglioma (CT), but none of the examined cases had SDH germline mutations (CSS) or somatic KIT/PDGFRA or BRAF mutations. SDH-deficient GISTs were often multiple and typically showed plexiform muscularis propria involvement and epithelioid hypercellular morphology. They were consistently KIT-positive and DOG1/Ano 1-positive and almost always smooth muscle actin negative. Tumor size and mitotic activity varied, and the tumors were somewhat unpredictable with low mitotic rates developing metastases. Gastric recurrences occurred in 11 patients, and peritoneal and liver metastases occurred in 8 and 10 patients, respectively. Lymph node metastases were detected in 5 patients, but lymphovascular invasion was present in >50% of cases studied; these 2 were not related to adverse outcome. Seven patients died of disease, but many had long survivals, even with peritoneal or liver metastases. All 378 nongastric GISTs and 34 gastric non-GIST mesenchymal tumors were SDHB positive. SDH-deficient GISTs constitute a small subgroup of gastric GISTs; they usually occur in children and young adults, often have a chronic course similar to that of pediatric and CT GISTs, and have potential association with paraganglioma, necessitating long-term follow-up.

Inflammatory Myofibroblastic Tumor Presenting With Esophageal Obstruction and an Inflammatory Syndrome

Inflammatory myofibroblastic tumor is a rare neoplasm of intermediate malignant potential. Although inflammatory myofibroblastic tumor occurs at multiple anatomic locations, an esophageal lesion is extremely rare. We describe a 43-year-old man who presented with severe dysphagia and an inflammatory syndrome, secondary to esophageal inflammatory myofibroblastic tumor. The patient was treated successfully with esophagectomy and remains disease free at 1 year. This case illustrates the complexities involved in managing a large esophageal myofibroblastic tumor and highlights that esophagectomy, rather than enucleation, should be the treatment of choice.

GIANT ULCERATED COLONIC LIPOMA MIMICKING MALIGNANCY

Lipomas of the colon are rare. The majority remain asymptomatic, although large (>2 cm) colonic lipomas may present with symptoms such as pain. Abstracts S139 obstruction, and bleeding. Giant lipomas of the colon may be misinterpreted as malignant masses. A 54 year old female was referred for colonoscopy for evaluation of a 2 month history of hematochezia, intermittent diarrhea and right-sided abdominal pain, associated with weight loss. Colonoscopy showed a large ulcerated, obstructing mass in the ascending colon. Abdominal CT scan revealed intussusception within the right colon adjacent to a lipomatous-appearing mass. The patient underwent a right hemicolectomy and histopathology revealed an ulcerated submucosal lipoma measuring 6×3.5×3 cm. The patient did well postoperatively. A lipoma may mimic carcinoma on colonoscopy and this alone warrants surgical removal. Colonic lipomas arise in the submucosa but occasionally extend into the muscularis propria. Endosonographic demonstration that the muscularis propria is not involved may allow for safe endoscopic resection after elevating the lesion with submucosal injection of saline. Large size (>2 cm), thick stalk, and involvement of muscularis propria are features associated with increased risk of perforation by endoscopic resection. When colonoscopy reveals a large or ulcerating mass that is suspicious for malignancy, surgical resection is recommended even if its composition is lipomatous on imaging studies.

Differentiation of colonic metaplasia from adenocarcinoma of urinary bladder

Colonic metaplasia and primary bladder adenocarcinoma are relatively uncommon entities that can have similar gross clinical appearances. Examples of colonic metaplasia histologically mimicking cancer have only rarely been reported. We retrospectively analyzed 38 cases of cystitis glandularis (18 cases of colonic metaplasia), 12 cases of adenocarcinoma of urinary bladder (two well-differentiated, WDA), and one in situ adenocarcinoma from the surgical pathology files of Johns Hopkins Hospital. Nine patients with colonic metaplasia had widespread lesions. Two showed superficial muscularis propria involvement, mimicking adenocarcinoma; one of these cases had been diagnosed as infiltrating WDA at both an academic center and a community hospital. Dissecting mucin pools were focally seen in four cases of widespread colonic metaplasia, also mimicking cancer. One of the nine cases showed minimal cytological atypia, but no cases showed mitoses or signet ring cells. Distinguishing WDA from colonic metaplasia was the finding in WDA of infiltrative architectural pattern (two of two), extensive muscle invasion (two of two), moderate anaplasia (one of two), mitotic figures (two of two), and extensive mucinous pools (one of two). The diagnosis of adenocarcinoma in situ was based on anaplasia. Clinically, colonic metaplasia may resemble cancer. Histologically, colonic metaplasia may mimic cancer based on extensive involvement of the lamina propria, focal mucinous pools, focal muscularis propria involvement, focal mild cytological atypia, and rare mitoses. Despite overlapping features with colonic metaplasia, the diagnosis of WDA is based on the greater degree and extent of these atypical findings in cancer.