Small Bowel Tumors Research Articles

Establishment of a surveillance program for anal cancer in Crohn's disease

This letter discusses the incidence of anal cancer among Crohn's disease (CD)-related malignancies. Patients with CD have been demonstrated to be at a higher risk of developing small bowel and colorectal cancers than healthy individuals. Although CD-associated anal cancer is relatively rare, patients with CD accompanied by anal or perianal lesions are at increased risk of anal cancer. Additionally, compared to ulcerative colitis, which is also an inflammatory disease, CD-related anal cancer is often detected at an advanced stage owing to the complexity of CD and is associated with a poor prognosis with frequent local recurrences. Therefore, the detection of early-stage cancer is crucial for improving the prognosis. However, the surveillance methods recommended for CD-related malignancies in the United States and Europe are similar to those for ulcerative colitis. They are not appropriate for detecting CD-related malignancies in the recto-anal region. Therefore, there is an urgent need for surveillance programs aimed at the early detection of malignant anorectal lesions in patients with CD.

Characteristics and prognosis of small bowel tumors: A retrospective study

BACKGROUND Small bowel tumors (SBTs) are a heterogeneous group of difficult-to-diagnose tumors that account for 2%-5% of all gastrointestinal tumors. Single-balloon enteroscopy greatly enhances the diagnosis and treatment of SBTs. However, few epidemiological studies have been conducted in Taiwan to determine the clinical profile of SBTs. AIM To investigate the clinical characteristics, managements and prognosis of SBTs in a medical center in Taiwan. METHODS The study enrolled 51 patients aged 58.9 ± 8.8 years (range, 22-93) diagnosed with SBTs from November 2009 to July 2021. We retrospectively recorded clinical characteristics, indications, endoscopic findings, pathological results, management, and outcomes for further analysis. RESULTS A male preponderance was observed (56.8%). The most common indications were suspected small intestinal tumors (52.9%) and obscure gastrointestinal bleeding (39.2%). The most common tumor location was the ileum (41.2%). The performance of imaging studies (P = 0.004) and the types of findings (P = 0.005) differed significantly between malignant and benign SBTs. The most frequent imaging finding was a small intestinal mass (43.1%). The top three malignant tumor types were gastrointestinal stromal tumors (GISTs), adenocarcinomas, and lymphomas. Moreover, the proportions of benign and malignant tumors were 27.5% and 72.5%, respectively. The survival rates of patients with malignant tumors in the GIST and non-GIST groups differed significantly (P = 0.015). Kaplan–Meier survival analysis showed a significant difference in survival between patients in the malignant and benign groups (P = 0.04). All patients with lymphoma underwent chemotherapy (n = 7/8, 87.5%), whereas most patients with GISTs underwent surgery (n = 13/14, 92.8%). CONCLUSION Patients with GISTs have a significantly higher survival rate than those with other malignant SBTs. Therefore, a large-scale nationwide study is warranted to evaluate the population-based epidemiology of SBTs.

RANK drives structured intestinal epithelial expansion during pregnancy.

During reproduction, multiple species such as insects and all mammals undergo extensive physiological and morphological adaptions to ensure health and survival of the mother and optimal development of the offspring. Here we report that the intestinal epithelium undergoes expansion during pregnancy and lactation in mammals. This enlargement of the intestinal surface area results in a novel geometry of expanded villi. Receptor activator of nuclear factor-κΒ (RANK, encoded by TNFRSF11A) and its ligand RANKL were identified as a molecular pathway involved in this villous expansion of the small intestine in vivo in mice and in intestinal mouse and human organoids. Mechanistically, RANK-RANKL protects gut epithelial cells from cell death and controls the intestinal stem cell niche through BMP receptor signalling, resulting in the elongation of villi and a prominent increase in the intestinal surface. As a transgenerational consequence, babies born to female mice that lack Rank in the intestinal epithelium show reduced weight and develop glucose intolerance after metabolic stress. Whereas gut epithelial remodelling in pregnancy/lactation is reversible, constitutive expression of an active form of RANK is sufficient to drive intestinal expansion followed by loss of villi and stem cells, and prevents the formation of Apcmin-driven small intestinal stem cell tumours. These data identify RANK-RANKL as a pathway that drives intestinal epithelial expansion in pregnancy/lactation, one of the most elusive and fundamental tissue remodelling events in mammalian life history and evolution.

Surgical and Oncologic Outcomes of Primary Tumor Resection in Patients with Small Intestinal Neuroendocrine Tumors: Results from a Single-Center Series Over a 15-Year Period.

The role of prophylactic primary tumor resection (PTR) in patients with small intestinal neuroendocrine tumors (SI-NETs) and unresectable liver metastases is a matter of debate. We aimed to evaluate outcomes in patients with SI-NETs who underwent PTR, according to the presence of metastasis and symptoms from primary. Data from patients who underwent PTR for SI-NETs from a single referral center (2007-2023) were prospectively collected. Patients were divided into three groups: non-metastatic (M0) and metastatic with primary tumor-related symptoms (MS) or metastatic asymptomatic (MA). Kaplan-Meier curves for overall survival (OS) and event-free survival (EFS) were generated and compared by group. Univariate and multivariable Cox regression analyses were performed to assess the significance of risk factors. Of 147 patients, 53 were M0, 23 were MS, and 71 were MA. Median follow-up was 26 months. The 5- and 10-year OS estimates were 100% and 100% in M0 patients, 82 and 21% in MS patients, and 89 and 80% in MA patients, respectively (p<0.001). Median EFS was 91 months overall and 43,126 months and not reached for the MS, MA, and M0 groups, respectively (p<0.001). In multivariable analysis, MS (hazard ratio [HR] 3.92, 95% confidence interval [CI] 1.71-9.52), functioning tumors (HR 1.98, 95% CI 1.03-3.81), and G2 grade (HR 3.20, 95% CI 1.64-6.85) were associated with a shorter EFS. In this large retrospective series, the MS group had a significantly worse OS and EFS compared with M0 and MA. This finding suggests that prophylactic PTR might benefit SI-NET patients with unresectable liver metastases, as symptom development could impair long-term prognosis after surgery.

Small intestinal metastasis from primary breast cancer: a case report and review of literature

Small intestinal metastasis from primary breast cancer remains a rare clinical occurrence. Despite extensive research into its clinicopathological features and treatment options, the specific pathogenesis and optimal management strategies remain incompletely understood. This case report presents a patient with breast cancer that metastasized to the small intestine. The primary breast tumor was diagnosed as classic invasive lobular carcinoma. Subsequent surgical intervention successfully addressed the intestinal obstruction and confirmed the metastatic origin of the small intestinal tumor. Interestingly, the metastatic lesions exhibited features suggestive of pleomorphic lobular carcinoma. A PET-CT scan was performed to evaluate the distant metastasis status of this patient. Notably, hormonal receptor status shifted from positive to negative, while HER2 expression changed from negative to low between the primary tumor and metastatic lesions. The presence of an undiagnosed pleomorphic component in the primary tumor might explain the disease’s progressive nature. In this case, systemic treatment with trastuzumab deruxtecan yielded favorable therapeutic outcomes. Overall, our findings suggest that re-evaluation of receptor status in breast cancer metastases is crucial for tailoring treatment strategies. Furthermore, a combination of palliative resection of small intestinal metastases and targeted therapy for HER2-low breast cancer may potentially improve survival.

Incidence and factors associated with heart disease in patients diagnosed with small bowel and broncho-pulmonary neuroendocrine tumors: a population-based analysis

Incidence and factors associated with heart disease in patients diagnosed with small bowel and broncho-pulmonary neuroendocrine tumors: a population-based analysis

The Value of Repeat 5-HIAA Measurements as a Predictor of Carcinoid Heart Disease: A Prospective 5-Year Follow-Up Study in Patients with Small Intestinal Neuroendocrine Tumors

The Value of Repeat 5-HIAA Measurements as a Predictor of Carcinoid Heart Disease: A Prospective 5-Year Follow-Up Study in Patients with Small Intestinal Neuroendocrine Tumors

Patterns of subsequent cancer incidence over time in patients with breast cancer.

Breast cancer survivors face a higher risk of subsequent primary cancers. This study investigated the patterns of subsequent cancer risk according to time since breast cancer diagnosis. Using data from the Surveillance, Epidemiology, and End Results program (2000-2018), we identified a cohort of 771,681 breast cancer survivors. Standard incidence ratios (SIR) were calculated by comparing the observed to the expected number of subsequent cancers over different follow-up periods since breast cancer diagnosis. Analyses were conducted for multiple cancer types, stratified by hormone receptor (HR) status and treatment of the first breast cancer, age, and race/ethnicity. Survivors experienced a 16% increased risk of subsequent cancer with the SIR continuing to increase with longer follow-up (SIR=1.04, 1.22, and 1.31 for 12-59, 60-119, and ≥120 months). This trend was driven primarily by a subsequent breast cancer, particularly among women <50 years, those with initial HR-negative cancer, and racial/ethnic minorities. The patterns of subsequent non-breast cancer risk varied by type. An early-onset and sustained increased risk was observed for subsequent leukemia, thyroid, soft tissue, melanoma, pancreas, and uterine cancer. A delayed increased risk was observed for subsequent esophagus, ovarian, oral cavity/pharynx, and lung cancer, while for small intestine, stomach, kidney, and colorectal cancer there was a decrease after an initial increased risk. Patterns in subsequent cancer risk since breast cancer diagnosis differ by cancer type and characteristics of the first breast cancer. These findings can inform etiology and tailored approaches to screening and prevention of subsequent cancers.

Higher Mortality Risk From Ovarian Carcinomas, Small Bowel Neoplasms, and B-Cell and Mucosa-Associated Lymphoid Tissue Lymphomas in Sjögren Syndrome Patients

Higher Mortality Risk From Ovarian Carcinomas, Small Bowel Neoplasms, and B-Cell and Mucosa-Associated Lymphoid Tissue Lymphomas in Sjögren Syndrome Patients

Is there a role for post-operative functional imaging in small intestinal neuroendocrine tumours resected with curative intent?

Is there a role for post-operative functional imaging in small intestinal neuroendocrine tumours resected with curative intent?

The Role of Small-Bowel Endoscopy in the Diagnosis and Management of Small-Bowel Neuroendocrine Tumours.

Neuroendocrine tumours (NETs) are relatively rare neoplasms but represent one of the most frequent types of primary small-bowel tumours. Their incidence is rising, and this is most likely because of their more frequent early-stage detection, physician awareness, and increasing availability and use of imaging and small-bowel endoscopic techniques, such as video capsule endoscopy and device-assisted enteroscopy, which enable the detection, localisation, and histological sampling of previously inaccessible and underdiagnosed small-bowel lesions. This review summarises the role of small-bowel endoscopy in the diagnosis and management of small-bowel NETs to assist clinicians in their practice. Small-bowel endoscopy may play a complementary role in the diagnosis of these tumours alongside other diagnostic tests, such as biomarkers, conventional radiology, and functional imaging. In addition, small-bowel enteroscopy may play a role in the preoperative setting for the identification and marking of these tumours for surgical resection and the management of rare complications, such as small-bowel variceal bleeding, in cases of portal hypertension due to the encasement of mesenteric vessels in fibrotic small-bowel NETs.

HPB SO32 - Outcomes Following Surgical Resection for Duodenal Adenocarcinoma – A Single Centre Experience

Abstract Background Duodenal adenocarcinomas are rare cancers and their clinico-oncological management pathways tend to follow that of small bowel tumours. The aim of this study was to determine the outcomes of patients undergoing surgical resection for duodenal adenocarcinoma. Method Retrospective data of all patients who underwent surgical resection for duodenal adenocarcinoma between January 2008 to December 2023 were included. Collated data included demographics, clinico-pathological features and survival outcomes. Results Thirty-one patients were included, with a mean age of 65.7 (± 9.6) years and a greater proportion were male patients (58.1%). The predominant site of the primary tumour was at D2 section of the duodenum (58.1%). The majority of patients required a pancreatico-duodenectomy (80.6%) and 58.1% experienced minor morbidity (Clavien-Dindo I-II) while 22.6% experienced major morbidity (Clavien-Dindo III-V). There were 4 (12.9%) peri-operative mortalities. Results The median post-operative follow-up was 29.7 (IQR 61.5) months. Only 37.0% of patients received adjuvant chemotherapy while 13 patients (48.1%) experienced disease recurrence. The 3- and 5-year overall survival was 44.3% and 33.3%, respectively, while the disease-free survival at 3 and 5 years were 37.0% and 29.6%, respectively. Patients who received adjuvant chemotherapy had a trend towards improved mean overall survival in comparison to patients who did not receive chemotherapy following surgery [80.3 vs 51.2 months; log rank 1.857, p=0.173]. Nevertheless, the median disease-free survival was similar between both groups [24.0 vs 26.0 months, log rank 0.016, p=0.901]. Patients who experienced major morbidity (Clavien-Dindo III-V) were significantly more likely to have a poorer median overall survival compared to patients with minor morbidity (Clavien-Dindo I-II) [72.1 vs 3.4 months; log rank 16.860, p&amp;lt;0.001]. Conclusion Major morbidity (Clavien-Dindo III-V) following surgery is associated with poorer overall survival. Patients who received adjuvant chemotherapy following surgical resection for duodenal adenocarcinoma may have a trend towards improved overall survival.

EGS SO18 - Entero-enteric intussusception secondary to a capillary haemangioma of the small bowel: A case of a diagnostic conundrum

Abstract Background This is a case of a 50 year-old female who presented with acute on chronic abdominal pain, and she was intra-operatively diagnosed with entero-enteric intussusception secondary to a large small bowel tumour . The video demonstrates the findings during the diagnostic laparoscopy. The lead point appeared to be a tumour and histopathology confirmed it is a benign capillary haemangioma. The patient had a long standing history of abdominal pain that was previously investigated on multiple occasions, but without a definitive diagnosis. Method This is an interesting case of a challenging diagnosis of a rare disease. The patient has been suffering for four years with unexplained upper abdominal pain not associated with weight loss, rectal bleed, or change in bowel habit, but had occasional anaemia. The patient had a normal abdominal US, multiple CTs where she was found to have a right renal stone and an OGD that showed gastritis and positive CLO test initially. A repeat OGD and colonoscopy were negative. While the patient was awaiting further investigations for profound iron deficiency anaemia she presented with acute abdomen and required emergency surgery. Results The patient presented to ED with excruciating colicky pain for one day, one episode of melena and nausea. She was haemodynamically stable, peritonitic with increased inflammatory markers, hb 86 g/dL and lactate of 2 mmol/L. The CT abdomen and pelvis showed small bowel intussusception with possible ischemia, therefore the patient underwent an emergency operation.The laparoscopy showed small bowel intussusception and the patient underwent mini laparotomy. The intussusception was reduced, the small bowel was viable and the lead point was a large size tumour.The patient underwent small bowel resection and primary anastomosis, and made good post operative recovery. Conclusion Rare conditions are hard to diagnose. Small bowel intussusception is rare and in adults is usually linked to serious underlying pathology. Capillary haemangioma of the small bowel is very rare too. The patient's symptoms and occassional anaemia can now be explained. Although the patient went through an appropriate work up at the time, her symptoms remained unexplained to some extent or they were linked to other potential causes. Only when the anaemia became profound the patient warranted further investigations. In retrospect, capsule endoscopy would have been inevitable, however the patient became acutely unwell and required an emergency surgery.

The effects of antioxidant administration in the early stages of radiation-induced tumorigenesis.

ApcMin/+ mouse was a model mouse for human familial adenomatous polyposis, and irradiation at an early age increases tumors in the small and large intestine. To study the effects of antioxidant administration on tumor incidence after continuous whole-body exposure to gamma rays, ApcMin/+ mice were exposed to a medium-dose-rate, 200mGy/d, from postnatal Day 0 to 21 of age or a high-dose-rate of 0.65Gy/min (total dose 4.2Gy) on postnatal Day 7. The dams and pups were supplied with the N-acetylcysteine (NAC) in drinking water (7g/L), from gestation Day 15 until weaning (21days-old). A significant increase in the number of intestinal tumors were observed in ApcMin/+ mice irradiated with high dose-rate gamma rays as compared with the non-irradiated controls, but there was no significant difference in tumor counts between the non-irradiated controls and the medium-dose rate irradiation groups. NAC administration did not have any significant effect at least at this dose. These results suggest that the supplementation of anti-oxidant at the early stage of tumorigenesis does not suppress the formation of irradiation-induced small intestinal tumors.

The effect of thyroid cancer on the survival of patients with digestive system tumors using SEER database

The number of cancer survivors worldwide is increasing every year, making secondary primary cancers (SPC) is a growing health threat. Studies have been conducted to investigate the risk of occurrence between digestive system tumors (DST) and thyroid cancer (TC). However, existing studies have tended to focus more on the risk of developing SPC and less on the impact of SPC on the survival of cancer survivors. In this study, using the Surveillance, Epidemiology, and End Results database, we aimed to explore the impact of TC on the survival of patients with DST by data between 2000 and 2018. The study employed the standardized incidence ratio to assess the relative risk of SPC, propensity score matching was conducted to mitigate confounding effects, Kaplan-Meier, Cox proportional risk model and competitive risk model were used to analyze the factors affecting the overall survival and cancer-specific survival. We furthermore explored the influence of pathological types and radiotherapy of TC on the survival of DST patients. 518,901 patients with DST only, 801 patients with TC occurring earlier than DST (TC-1st), and 744 patients with DST occurring earlier than TC (DST-1st) were included. The total incidence rate of small intestine cancer after TC was higher than that of the general population, and the incidence of TC after DST was higher than in the general population. DST patients with a history of TC had better overall survival and lower cancer-specific mortality and this difference was particularly significant in patients with DST-1st. In addition, radiotherapy for TC had no effect on cancer-specific mortality in patients with DST.

EPID-27. THE INCIDENCE OF BRAIN METASTASIS IN GASTROINTESTINAL CANCER ACCORDING TO PRIMARY SITE AND STAGE: A 15-YEAR SINGLE INSTITUTIONAL ANALYSIS

Abstract Gastrointestinal (GI) cancers are a diverse group of cancers including pancreatic, gastric/gastroesophageal junction/esophageal (G/GEJ/E), colorectal (CRC), hepatocellular (HCC), biliary tract (BT), and anal origin cancers. The risk of developing brain metastasis (BrM) is not well characterized. The aim was to determine the incidence of BrM among all GI cancer patients at Princess Margaret Hospital (PM). We included patients diagnosed with GI cancer presenting from 2005-2020, captured prospectively in our institutional registry. These patients were cross-referenced with our radiotherapy database, where radiotherapy for brain metastases (BrM) was used as a proxy for the brain metastases development. Cumulative incidences (CI) of BrM diagnoses were calculated using death as a competing risk. Overall survival (OS) was estimated using the Kaplan Meier method. The registry accounted for 22,188 patients. The median age of the cohort was 64. Most common primary sites are CRC adenocarcinoma, pancreatic adenocarcinoma, G/GEJ/E adenocarcinoma were 31.52%/11.71%/10.25%. The 15-year CI for BrM for the entire cohort was 1.65%, and for CRC, small bowel, anal, pancreatic, G/GEJ/E, HCC, and BT cancers were 2.69%/2.49%/1.30%/0.5%/3.52%/ 0.05% /0.4% (p &amp;lt; 0.001) and Stage I-IV disease were 0.39%/0.81%/1.2%/3.1%, respectively (p &amp;lt; 0.001). 5 year CI for HER2 positive G/GEJ/E patients was 19.5%. Median OS from initial presentation for those with BrM was 25.13 months. On univariable analysis, chemotherapy receipt [HR 1.916, p &amp;lt; 0.001], Stage IV at presentation [HR 3.991, p &amp;lt; 0.001], and G/GEJ/E primary [HR 1.357, p &amp;lt; 0.001] predicted for higher risk of BrM. Multivariable analysis confirmed that receipt of chemotherapy and Stage IV disease predicted a higher risk for BrM and pancreatic, HCC, and BT cancers predicted for lower BrM. We observed that among patients diagnosed with GI cancers, Stage IV disease predicted higher risk for developing BrM and were more likely to receive chemotherapy.

Molecular and Clinicopathologic Impact of GNAS Variants Across Solid Tumors.

The molecular drivers underlying mucinous tumor pathogenicity are poorly understood. GNAS mutations predict metastatic burden and treatment resistance in mucinous appendiceal adenocarcinoma. We investigated the pan-cancer clinicopathologic relevance of GNAS variants. We assessed 58,043 patients with Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (IMPACT)-sequenced solid tumors to identify oncogenic variants, including GNAS, associated with mucinous tumor phenotype. We then performed comprehensive molecular analyses to compare GNAS-mutant (mut) and wild-type tumors across cancers. Gene expression patterns associated with GNAS-mut tumors were assessed in a The Cancer Genome Atlas cohort. Associations between GNAS variant status and peritoneal metastasis, first-line systemic therapy response, progression-free survival (PFS), and overall survival (OS) were determined using a propensity-matched subcohort of patients with metastatic disease. Mucinous tumors were enriched for oncogenic GNAS variants. GNAS was mutated in >1% of small bowel, cervical, colorectal, pancreatic, esophagogastric, hepatobiliary, and GI neuroendocrine cancers. Across these cancers, GNAS-mut tumors exhibited a generally conserved C-to-T mutation-high, aneuploidy-low molecular profile with co-occurring prevalent KRAS variants (65% of GNAS-mut tumors) and fewer TP53 alterations. GNAS-mut tumors exhibited recurrently comutated alternative tumor suppressors (RBM10, INPPL1) and upregulation of MAPK and cell surface modulators. GNAS-mut tumors demonstrate an increased prevalence of peritoneal metastases (odds ratio [OR], 1.7 [95% CI, 1.1 to 2.5]; P = .006), worse response to first-line systemic therapy (OR, 2.2 [95% CI, 1.3 to 3.8]; P = .003), and shorter PFS (median, 5.6 v 7.0 months; P = .047). In a multivariable analysis, GNAS mutated status was independently prognostic of worse OS (hazard ratio, 1.25 [95% CI, 1.01 to 1.56]; adjusted P = .04). Across the assessed cancers, GNAS-mut tumors exhibit a conserved molecular and clinical phenotype defined by mucinous tumor status, increased peritoneal metastasis, poor response to first-line systemic therapy, and worse survival.

Primitive Resectable Small Bowel Cancer Clinical-Pathological Analysis: A 10-Year Retrospective Study in a General Surgery Unit.

Introduction: Small bowel cancer is very rare; although the incidence of adenocarcinoma and other anatomopathological forms has increased recently, the diagnosis and treatment of this disease are still debatable because of the clinical heterogeneity and the absence of studies including a large number of patients. Materials and Methods: We performed a retrospective study over 10 years in which we analyzed the clinical, imaging, and anatomopathological data of 46 patients hospitalized in a surgery clinic and diagnosed with small bowel cancer (duodenum, jejunum, and ileum). Results: After clinical assessment of these patients, including complications (occlusion, bleeding, and perforation), the CT scan established the diagnosis in over 90% of the cases of the complicated form of the disease. Surgery has a curative role in localized cancers; tumor location, local invasion, the presence of locoregional lymph nodes, and the number of multiple tumors influence the type of surgery. The conventional pathological exam was completed via immunohistochemical staining. Adjuvant oncological treatment was performed after surgery (according to the guidelines); in patients with exceptional histopathological forms, the therapy was personalized. Conclusions: Most small bowel cancers were diagnosed with complications (occlusion and bleeding); the tumor type, location, and presence of multiple bowel cancers significantly influenced its management. Independently of the surgical resection (R0/R1 or R2), the prognosis of the disease depends on the tumor aggressivity, location (single/multiple), and locoregional node invasion.

Efficacy of traditional Chinese medicine in the conservative management of complete small intestinal obstruction post-gastric cancer surgery: A case report

In this case report, we describe the successful treatment of a patient with complete small bowel obstruction following gastric cancer surgery, employing an integrated approach of traditional Chinese medicine and Western medicine. Initial treatment consisted of conventional biomedical interventions, including intestinal obstruction catheterization, but after 16 days without improvement, surgical intervention was recommended. The patient, however, refused surgery and opted for treatments based on traditional Chinese medicine. Comprehensive traditional Chinese medicine therapies such as acupuncture, moxibustion, flash cupping, oral administration of compound herbal formulas, and enemas using Chinese herbal medicine were implemented alongside modern medical care. The obstruction resolved, and the patient was discharged without requiring surgery. Follow-up revealed no recurrence of the condition. This case highlights the potential of integrating traditional Chinese medicine with Western medical practices in the conservative management of complete small bowel obstruction, offering a reference for clinical application.

Solitary Loss of PMS2 in a patient with Colon carcinoma

Abstract Introduction/Objective In the United States, there are about 150,000 new cases of Colorectal cancer (CRC) and about 50,000 CRC related deaths each year. Hereditary nonpolyposis colorectal cancer (Lynch Syndrome) accounts for 2% - 4% of CRC. It is characterized by germline mutations in mismatch repair (MMR) genes - MLH1, MSH2, MSH6 and PMS2. Patients with Lynch syndrome have up to an 80% lifetime risk (LTR) of CRC and up to 60% LTR of endometrial cancer. Lynch syndrome patients also have an associated LTR of ovarian cancer (38%), upper urologic tract cancer (18%), gastric cancer (13%), small bowel cancer (6%), hepatobiliary tract cancer (4%), and brain tumors (3% - usually glioblastoma). Methods/Case Report A 76-year-old man with history of moderately differentiated colorectal adenosarcoma involving the transverse colon and a recently diagnosed grade group 5 (Gleason 4 + 5) prostate adenocarcinoma, currently being managed at an outside hospital. The case was sent to UAB for DNA MMR/microsatellite instability (MSI) status evaluation testing. Immunostaining showed loss of PMS2 and intact expression of MLH1, MSH2 and MSH6. These results were confirmed by the IdyIIa MSI assay which detected microsatellite instability in 5 of 7 markers and negative for BRAF V600E variant confirming microsatellite instable tumor. Results (if a Case Study enter NA) NA Conclusion Solitary loss of PMS2 in colonic adenocarcinoma is uncommon and may be caused by an underlying germline mutation of MLH-1 or PMS2, thus could represent Lynch Syndrome. Our patient’s age doesn’t favor Lynch syndrome. Next step would be to perform MLH-1 promoter methylation to confirm sporadic nature of carcinoma. Somatic methylation of the MLH1 promoter occurs in approximately 80% of CRC with defective MMR. Prostate cancer is not currently considered a part of Lynch syndrome.