Schwannoma of the rectum: A case report and literature review

Schwannoma is a tumor originating from the Schwann cells. Gastrointestinal schwannomas are uncommon stromal tumors of the intestinal tract and, in particular, rectal schwannomas are extremely rare. In fact, it is well established that schwannomas appear more frequently in the stomach and in the small intestine, while location in the colon or in the rectum is uncommon. Reading the literature, only few cases of rectal schwannoma have been reported. Their diagnosis is confirmed by the immunohistochemical panel (S-100 protein). When these tumors are located in the colon and in the rectum, radical excision with wide margins is mandatory, due to their tendency to recur locally or become malignant, if left untreated. In the present study, we describe a case of a rectal schwannoma occured in a 72-year-old man, presented as a small polypoid lesion, which was successfully removed in toto by hot-biopsy, during the same endoscopy, due to the dimensons. No recurrence of the lesion was observed after 6 mo of follow-up.

Case of rectal angioleiomyoma in a female patient

Angioleiomyoma represents a benign stromal tumor, which usually occurs in the subcutaneous tissue of the extremities, although its occurrence in the gastrointestinal tract is very rare. A case of rectal angioleiomyoma in a 40 year-old female patient is described here. Six months earlier, the patient suffered from periodical prolapse of an oval tumor from the anus, along with difficulties in bowel movement. A transanal extirpation of the tumor was performed. This is the first reported case in the English literature of a patient presenting with prolapsed angioleiomyoma of the rectum. During the immediate postoperative period, as well as 6 mo later, the patient had an unremarkable postoperative recovery.

Metaplastic ossification in a juvenile rectal polyp: a rare histological finding

An osseous metaplasia is a phenomenon which has been described in a wide variety of tissue types with respect to both neoplastic and non-neoplastic conditions. However, an osseous metaplasia is exceedingly rare in colonic polyps. We are herein representing a case of osseous metaplasia in a juvenile rectal polyp in a six year old boy, with review of the literature on the suggested mechanisms of its aetiology.

Diffuse hemolymphangioma of the rectum: A report of a rare case

Intestinal hemolymphangioma is a rare vascular and lymphatic malformation and is manifested as anaemia and recurrent alimentary tract hemorrhage. Few cases of hemolymphangioma occurring in small intestine, spleen, esophagus and other organs have been reported. We herein report a case of a 37-year-old man with severe rectal bleeding. Digital examination revealed nodular mucosa. No rectal mass was palpated, but bleeding in the ampulla was detected. Colonoscopy revealed an extensive hypervascular submucosal lesion arising from the rectosigmoid junction colon to the distal edge of the anus. Endoscopic ultrasonography demonstrated an extensive anechoic mass with clear edge. Magnetic resonance imaging (MRI) showed a significant thickness of the rectal wall, extending to the distal edge of the anus, with a narrowing lumen. A sphincter-saving rectal surgery was performed. Due to a lack of knowledge of the clinical, endoscopic and radiological features, preoperative recognition of hemolymphangioma is not easy. Computed tomography and MRI are helpful in confirming the diagnosis, and defining the extent and invasion of the lesion. For the low malignant potential tumors, a sphincter-saving rectal surgery is recommended after a full evaluation of the tumor.

Histopathologic study of the rectum in 1,464 consecutive rectal specimens in a single Japanese hospital: II. malignant lesions

The author investigated histopathology of 1,464 consecutive rectal specimens in of our pathology laboratory in Japan. A review of pathological reports was done by computer. Observation of histological slides was performed, when appropriate. The rectal specimens were composed of 1,041 benign lesions and 423 malignant lesions. The 423 malignant lesions were composed of 367 cases of primary rectal carcinoma, 41 cases of carcinoma in adenoma, 7 cases of neuroendocrine tumor, 3 cases of malignant lymphoma, 2 cases of gastrointestinal stromal tumors (GIST), and 3 cases of metastatic carcinoma. Of the 367 cases of primary rectal carcinoma, 37 cases were early carcinomas whose invasion was limited up to the submucosa (early rectal carcinoma). The remaining 330 cases were advanced carcinoma invading beyond the proper muscle layer. The histological types were well differentiated adenocarcinoma in 197 cases, moderately differentiated adenocarcinoma in 129 cases, poorly differentiated adenocarcinoma in 10 cases, mucinous adenocarcinoma in 24 cases, signet ring cell carcinoma in 6 cases, squamous cell carcinoma in 1 case In the 41 cases of carcinoma in adenoma, the carcinoma was well to moderately differentiated adenocarcinoma, and all cases were early carcinomas without invasion or with little invasions to subserosa. The size of carcinoma in adenoma was as follows: < 10 mm, 5 cases; 10-15 mm, 8 cases; 15-20 mm, 23 cases; > 20mm, 5 cases. The background adenoma was as follows: tubular adenoma (n=15), tubulo-villous adenoma (n=14), and villous adenoma (n=12). The 7 cases of neuroendocrine carcinoma consisted of 6 low grade neuroendocrine tumors (carcinoids) and 1 high grade neuroendocrine carcinoma (small cell carcinoma). All were submucosal lesions. Immunohistochemically, the tumor cells were positive for two or more of synaptophysin, chromogranin, neuron-specific enolase, CD56. In small cell carcinoma, KIT and PDGFRA were consistently positive. The 3 cases of malignant lymphoma were diffuse large B-cell lymphomas positive for CD20 and CD79a and negative for NK/T cell markers. The two cases of GIST was spindle cell type, and the risk was intermediate. Kit mutations were recognized in both GISTs. No PDGFRA mutations were seen. Of the 3 metastatic carcinomas, one was a metastasis from prostatic adenocarcinoma, and the remaining two was adenocarcinoma of unknown primary sites.

Inflammatory fibroid polyp of rectum mimicking rectal cancer

Inflammatory fibroid polyps (IFPs) are rare benign tumors of the rectum. Mutation and activating platelet-derived growth factor receptor alpha (PDGFRA) contribute to tumor development. We present a case of IFPs in the middle rectum that mimic rectal cancer. A 65-year-old woman presented with the symptom of fresh blood in the stool and body weight loss of 6 kg in the preceding 3 weeks. A rectal polypoid tumor was noted upon digital examination. Sigmoidoscopy showed a middle rectal tumor measuring 3 × 2.7 cm with obstruction. Computed tomography (CT) scans of the abdomen showed a rectal tumor that had invaded the sacral bone and was associated with four enlarged lymph nodes greater than 1 cm. The radiological report suggested a diagnosis of rectal cancer with lymph node metastases. To remove the obstruction, the patient was initially treated with excision of the tumor and loop sigmoidal colostomy to the abdomen wall. Total mesorectal resection of rectal and sacral tumor followed 10 days later. Histopathological examination of the rectal and sacral tumor showed proliferation of vessels, fibroblast-like spindle cells, and mixed inflammatory cells, including the plasma cells and eosinophils. The spindle cells were diffusely positive to PDGFRA and were focal positive to CD34 and smooth muscle actin. Based on histopathological and immunohistochemical findings, the diagnosis of IFP is indicated. This was the first reported case of IFPs of the rectum presenting with lymph node enlargement and attachment to the sacrum mimicking rectal cancer.

Effect of biofeedback therapy in constipation according to rectal sensation

BACKGROUND/AIMS

The pathophysiologic mechanism of rectal hyposensitivity (RH) is not well documented, and the significance of RH in biofeedback therapy (BFT) has not been evaluated. Thus, we aimed to assess the effect of BFT in constipated patients according to the presence of RH.

METHODS

Five hundred and ninety constipated patients (238 males and 352 females) underwent anorectal physiologic assessments. Of these, anorectal manometry was performed before and after BFT in 244 patients (63 RH and 181 non-RH patients).

RESULTS

The success rate of BFT was 56% in the RH and 61% in the non-RH group (p=0.604). The measurements of resting pressure, squeezing pressure, desire to defecate volume, urge to defecate volume, and maximum volume were decreased after BFT in the RH group (p<0.05), whereas only resting and squeezing pressures were decreased in the non-RH group (p<0.05). Among the RH group, individuals who responded to BFT showed decreased resting pressure, squeezing pressure, desire to defecate, urge to defecate, and maximum volume and increased balloon expulsion rate; among those who did not respond to BFT, only desire to defecate volume was improved.

CONCLUSIONS

In constipated patients with RH, changes of anorectal manometric findings differed in comparison to patients without RH. The responses to BFT showed both anorectal muscle relaxation and restoration of rectal sensation.

The mTOR Pathway and the Role of Energy Balance Throughout Life in Colorectal Cancer Etiology and Prognosis: Unravelling Mechanisms Through a Multidimensional Molecular Epidemiologic Approach

Timing of exposure to lifestyle factors that influence energy balance may differentially affect colorectal cancer (CRC) risk and prognosis. Caloric restriction in youth and short stature, as markers of early-life exposures, have shown to decrease CRC risk, whereas large body size and low physical activity levels in adulthood are established risk factors for CRC. Regarding prognosis, overweight, sarcopenia, and their co-occurrence (sarcopenic obesity) may negatively influence the health and quality of life of CRC survivors. There is mechanistic support for disruption of the mammalian target of rapamycin (mTOR) pathway as an underlying mechanism possibly driving these associations, because mTOR integrates signals from growth factors, nutrients, mutagens, and hormones to induce cell proliferation, resistance to apoptosis, and autophagy. However, epidemiologic evidence connecting mTOR to energy-balance-related CRC throughout the lifespan is scarce. This perspective proposes how multidimensional molecular epidemiologic studies can shed light on the etiology and prognosis of energy-balance-related CRC.

Rectal diverticulum in a terrier dog: A case report

Rectal diverticulum is a rare condition in dogs characterized by formation of a pouch or sac due to hernial protrusion of the mucous membranes through a defect in the muscular coat of the rectum. A 12-year-old male terrier dog was admitted with a history of a left perineal swelling, dyschezia and tenesmus during the last five months. Digital rectal examination identified a weakness in the left pelvic diaphragm and feces-filled sac within the lateral wall of the rectum. Positive contrast radiography showed a marked solitary diverticulum (3.5 × 4 × 4.5 cm) with wide-orifice neck arising from the left rectal wall. Using a lateral approach, a large rectal diverticulum was found and diverticulectomy following standard herniorrhaphy was performed. The dog recovered uneventfully with no signs of dyschezia during the next three years. Diverticulectomy by lateral approach and perineal herniorrhaphy produced excellent results.

Short-term outcomes of laparoscopic total mesorectal excision compared to open surgery

AIM: To investigate the short-term outcome of laparoscopic total mesorectal excision (TME) in patients with mid and low rectal cancers.

METHODS: A consecutive series of 138 patients with middle and low rectal cancer were randomly assigned to either the laparoscopic TME (LTME) group or the open TME (OTME) group between September 2008 and July 2011 at the Department of Colorectal Cancer of Shanghai Cancer Center, Fudan University and pathological data, as well as surgical technique were reviewed retrospectively. Short-term clinical and oncological outcome were compared in these two groups. Patients were followed in the outpatient clinic 2 wk after the surgery and then every 3 mo in the first year if no adjuvant chemoradiation was indicated. Statistical analysis was performed using SPSS 13.0 software.

RESULTS: Sixty-seven patients were treated with LTME and 71 patients were treated with OTME (sex ratio 1.3:1 vs 1.29:1, age 58.4 ± 13.6 years vs 59.6 ± 9.4 years, respectively). The resection was considered curative in all cases. The sphincter-preserving rate was 65.7% (44/67) vs 60.6% (43/71), P = 0.046; mean blood loss was 86.9 ± 37.6 mL vs 119.1 ± 32.7 mL, P = 0.018; postoperative analgesia was 2.1 ± 0.6 d vs 3.9 ± 1.8 d, P = 0.008; duration of urinary drainage was 4.7 ± 1.8 d vs 6.9 ± 3.4 d, P = 0.016, respectively. The conversion rate was 2.99%. The complication rate, circumferential margin involvement, distal margins and lymph node yield were similar for both procedures. No port site recurrence, anastomotic recurrence or mortality was observed during a median follow-up period of 21 mo (range: 9-56 mo).

CONCLUSION: Laparoscopic TME is safe and feasible, with an oncological adequacy comparable to the open approach. Further studies with more patients and longer follow-up are needed to confirm the present results.

Non-steroidal anti-inflammatory drugs in colorectal surgery: A risk factor for anastomotic complications?

In a recent article, Gorissen et al report on 795 patients with primary colorectal anastomosis operated on during the period 2008-2010 for different colorectal conditions at two centres. The leakage rate was significantly higher among patients who were administered non-steroidal anti-inflammatory drugs (NSAIDs) in the perioperative course. A dose-response relationship could also be traced, where longer NSAID use yielded a higher risk of anastomotic breakdown. However, as this study is observational in design, confounding by indication may be present and there is also a risk of residual confounding from unmeasured covariates. Moreover, the question whether different affinity for the cyclooxygenase enzyme is important in different NSAIDs seems to be largely unanswered. The results, conclusions and clinical relevance of the aforementioned study, including the possible effects of different types of NSAIDs, are discussed. While acknowledging that this study represents the best attempt so far in establishing the causal relationship between perioperative NSAID use and anastomotic leakage, the need for further research in this important area is underlined.

Pathological evaluation of gastrointestinal endoscopic submucosal dissection materials based on Japanese guidelines

Endoscopic surgery first started as snare polypectomy and then progressed to endoscopic mucosal resection (EMR). In order to resect a lesion that is more than 2 cm, endoscopic submucosal dissection (ESD) was developed. ESD therapy has now been established and is being used for early stage neoplastic lesions in the stomach, colon, esophagus, larynx and pharynx. In ESD specimens, we deal with relatively small lesions; therefore, more meticulous and precise pathological diagnosis is required compared to that in surgically resected specimens. In addition, we should be expert in the eligibility criteria of the different organs for ESD therapy. Here, we explain the biopsy diagnosis, including the Japanese group classification as well as the Vienna classification, handling the specimen, including fixation, photography, cutting and paraffin embedding, histological type, depth, vascular invasion and evaluation of the surgical margins, based on the latest Japanese guidelines. Japanese histopathology diagnostic criteria for the stomach, colon and esophagus are also described. We also demonstrate some examples of those mentioned above.

Dedifferentiated liposarcoma of the rectum: A case report

Liposarcoma is one of the most common soft tissue sarcomas found in adults, and it usually occurs in the retroperitoneum and the extremities. Here, we describe a case of dedifferentiated liposarcoma originating from a well-differentiated liposarcoma of the mesorectum that presented as a protruding mass in the rectal lumen. Hartmann’s operation with total mesorectal excision was performed and the tumor was removed radically. No management guidelines are currently available for liposarcoma of the rectum. We propose that complete surgical resection be required for the treatment of rectal liposarcoma and that a long-term detailed follow up is necessary.

[3.0T MRI with a high resolution protocol for the study of benign disease of the anus and rectum. Part 2: Anorectal inflammatory disease. Postsurgical anatomy and complications after treatment]

Benign anorectal disease comprises a broad group of processes with very diverse origins; these processes may be congenital or acquired as well as inflammatory or tumor related. However, benign anorectal disease has received less attention in the scientific literature than malignant disease. In this second part of this image-based review of benign anorectal disease, we describe the most common inflammatory and fistulous diseases, the postsurgical anatomy, and complications that can occur after surgical treatment or radiotherapy for anorectal disease.

[3.0 T MRI with a high resolution protocol for the study of benign disease of the anus and rectum. Part one: High resolution protocol for 3.0 T MRI, anatomic review, benign tumors, and congenital or acquired alterations of the sphincter complex]

Benign anorectal disease comprises a broad group of processes with very diverse origins; these processes may be congenital or acquired as well as inflammatory or tumor related. However, benign anorectal disease has received less attention in the scientific literature than malignant disease. We present an image-based review of the most common benign diseases of the anus and rectum. In this first part, we review the anatomy of the region and provide a brief description of the peculiarities of the high resolution protocol that we use with 3.0 T MRI. We go on to describe the most common benign anorectal tumors and developmental cystic lesions, together with their differential diagnoses, as well as congenital and acquired anomalies of the anorectal sphincter complex.

Assessment of the validity of the clinical pathway for colon endoscopic submucosal dissection

AIM: To determine the effective hospitalization period as the clinical pathway to prepare patients for endoscopic submucosal dissection (ESD).

METHODS: This is a retrospective observational study which included 189 patients consecutively treated by ESD at the National Cancer Center Hospital from May 2007 to March 2009. Patients were divided into 2 groups; patients in group A were discharged in 5 d and patients in group B included those who stayed longer than 5 d. The following data were collected for both groups: mean hospitalization period, tumor site, median tumor size, post-ESD rectal bleeding requiring urgent endoscopy, perforation during or after ESD, abdominal pain, fever above 38  °C, and blood test results positive for inflammatory markers before and after ESD. Each parameter was compared after data collection.

RESULTS: A total of 83% (156/189) of all patients could be discharged from the hospital on day 3 post-ESD. Complications were observed in 12.1% (23/189) of patients. Perforation occurred in 3.7% (7/189) of patients. All the perforations occurred during the ESD procedure and they were managed with endoscopic clipping. The incidence of post-operative bleeding was 2.6% (5/189); all the cases involved rectal bleeding. We divided the subjects into 2 groups: tumor diameter ≥ 4 cm and < 4 cm; there was no significant difference between the 2 groups (P = 0.93, χ² test with Yates correction). The incidence of abdominal pain was 3.7% (7/189). All the cases occurred on the day of the procedure or the next day. The median white blood cell count was 6800 ± 2280 (cells/μL; ± SD) for group A, and 7700 ± 2775 (cells/μL; ± SD) for group B, showing a statistically significant difference (P = 0.023, t-test). The mean C-reactive protein values the day after ESD were 0.4 ± 1.3 mg/dL and 0.5 ± 1.3 mg/dL for groups A and B, respectively, with no significant difference between the 2 groups (P = 0.54, t-test).

CONCLUSION: One-day admission is sufficient in the absence of complications during ESD or early post-operative bleeding.

Gastrointestinal stromal tumour of the rectum: a report of two cases

Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal tumours of the gastrointestinal tract in adults, although rectal localisation of these tumours is very rare. We report here two cases of rectal stromal tumours in a 77-year-old woman and a 65-year-old man, confirmed by histology and immunohistochemistry. Surgery for rectal GIST patients is the standard treatment and adjuvant imatinib, a tyrosine kinase inhibitor, is indicated for GISTs with a high risk of malignancy, as well as in the case of metastatic or unresectable tumours.

Spontaneous perforation of an intramural rectal hematoma: Report of a case

Spontaneous hematomas are rare and most occur secondary to hematologic disorders or during anticoagulant therapy. Most spontaneous hematomas occur above the sigmoid colon, and rarely in the rectum. Herein we present the case of a patient with a spontaneous perforating hematoma of the rectum who presented with severe abdominal pain after a bloody stool. The hemoglobin level decreased by 33 g/L within 20 h. An abdominal sonogram showed a hydrops in the lower abdomen with a maximum depth of 7.0 cm. A hematoma, 8 cm × 6 cm × 5 cm in size, was noted intra-operatively in the rectosigmoid junction, with a 1.5-cm perforation in the hematoma and active hemorrhage. Thus, a partial rectectomy and sigmoidostomy were performed. Three months later, a second operative procedure to re-establish intestinal continuity was performed. The patient is in good condition 12 mo after the last surgery. In addition to this case, the causes of spontaneous perforating hematomas and the treatment are discussed.

A case of primary ovarian lymphoma presenting as a rectal submucosal tumor

Primary ovarian lymphoma is a rare malignancy whose symptoms or signs are usually nonspecific. In this article, we report a very rare case initially presenting as a rectal submucosal-tumor-like lesion with a defecation disturbance caused by primary ovarian lymphoma with bilateral involvement. A 42-year-old woman visited chungnam national university hospital complaining of persistent defecation disturbance for 6 months. Colonoscopy demonstrated compression of the rectum by an extrinsic mass mimicking a rectal submucosal tumor. Magnetic resonance imaging detected bilateral ovarian tumors, 9.3 cm and 5.4 cm each in diameter, compressing the rectum without enlarged lymph nodes. The diagnosis was established following a bilateral adnexectomy and histological studies of the excised tissue. The tumor was classified as a diffuse large B-cell lymphoma. The patient was prescribed six cycles of standard CHOP (cyclophosphamide, hydroxydaunorubicin, vincristine, prednisolone) regimen and is presently on treatment.

B1a lymphocytes in the rectal mucosa of ulcerative colitis patients

AIM: To assess B1a cell expression in the rectal mucosa of ulcerative colitis (UC) patients in comparison with healthy controls.

METHODS: Rectal mucosa biopsies were collected from 15 UC patients and 17 healthy controls. CD5⁺ B cells were analysed by three colour flow cytometry from rectal mucosal samples after mechanical disaggregation by Medimachine^®. Immunohistochemical analysis of B and T lymphocytes was also performed. Correlations between, on the one hand, rectal B1a cell concentrations and, on the other, erythrocyte sedimentation rate and C-reactive protein levels and clinical, endoscopic and histological disease activity indices were evaluated.

RESULTS: Rectal B-lymphocyte (CD19⁺/CD45⁺) rate and concentration were higher in UC patients compared with those in healthy controls (47.85% ± 3.12% vs 26.10% ± 3.40%, P = 0.001 and 501 ± 91 cells/mm²vs 117 ± 18 cells/mm², P < 0.001); Rectal B1a cell density (CD5⁺CD19⁺) was higher in UC patients than in healthy controls (85 ± 15 cells/mm²vs 31 ± 6.7 cells/mm², P = 0.009). Rectal B1a cell (CD5/CD19⁺) rate correlated inversely with endoscopic classification (Rs = -0.637, P < 0.05).

CONCLUSION: B1a lymphocytes seem to be involved in the pathogenesis of UC, however, the role they play in its early phases and in disease activity, have yet to be defined.

Can intraluminal devices prevent or reduce colorectal anastomotic leakage: A review

Colorectal anastomotic leakage is a serious complication of colorectal surgery, leading to high morbidity and mortality rates. In recent decades, many strategies aimed at lowering the incidence of anastomotic leakage have been examined. The focus of this review will be on mechanical aids protecting the colonic anastomosis against leakage. A literature search was performed using MEDLINE, EMBASE, and The Cochrane Collaborative library for all papers related to prevention of anastomotic leakage by placement of a device in the colon. Devices were categorised as decompression devices, intracolonic devices, and biodegradable devices. A decompression device functions by keeping the anal sphincter open, thereby lowering the intraluminal pressure and lowering the pressure on the anastomosis. Intracolonic devices do not prevent the formation of dehiscence. However, they prevent the faecal load from contacting the anastomotic site, thereby preventing leakage of faeces into the peritoneal cavity. Many attempts have been made to find a device that decreases the incidence of AL; however, to date, none of the devices have been widely accepted.

Superiority of laparoscopic rectal surgery: Towards a new era

While laparoscopic colon surgery has been established to some degree over this decade, laparoscopic rectal surgery is not standard yet because of the difficulty of making a clear surgical field, the lack of precise anatomy of the pelvis, immature procedures of rectal transaction and so on. On the other hand, maintaining a clear surgical field via the magnified laparoscopy may allow easier mobilization of the rectum as far as the levetor muscle level and may result less blood loss and less invasiveness. However, some unique techniques to keep a clear surgical field and knowledge about anatomy of the pelvis are required to achieve the above superior operative outcomes. This review article discusses how to keep a clear operative field, removing normally existing abdominal structures, and how to transact the rectum and restore the discontinuity based on anatomical investigations. According to this review, laparoscopic rectal surgery will become a powerful modality to accomplish a more precise procedure which has been technically impossible so far, actually entering a new era.

Invasive lobular breast cancer presenting an unusual metastatic pattern in the form of peritoneal and rectal metastases: a case report

Gastrointestinal metastases from invasive lobular breast cancer are uncommon with the stomach and small intestines being the most common metastatic sites. Peritoneal and rectal metastases are very rare and only rarely occur as the first manifestation of disease. We herein report the case of a 47-year-old woman who presented with abdominal carcinomatosis as a first sign of invasive lobular breast carcinoma (ILC). Identifying the most important immunohistochemical markers for ILC: gross cystic disease fluid protein 15, estrogen and progesterone receptors enabled a correct diagnosis. After a six year disease-free period, relapse occurred with severe obstruction due to rectal metastasis from lobular breast carcinoma. Since there was no widespread metastatic disease, surgery with concomitant hormonal therapy was performed.

Is rectal cancer prone to metastasize to lymph nodes than colon cancer?

The biology of colorectal cancer differs according to its location within the large intestine. A report published in a previous issue of World Journal of Gastroenterology (November 2010) evaluated the importance of tumor location as a risk factor for lymph node metastasis in colorectal cancer, and showed that rectal cancer is prone to metastasize to lymph nodes as compared with colon cancer. However, in order to conclude that the tumor location is independently associated with the occurrence of lymph node metastasis, it is necessary to consider a selection bias or other patient- and tumor-related factors carefully.

Management of early gastrointestinal neuroendocrine neoplasms

Neuroendocrine neoplasms (NENs) of the stomach, duodenum, appendix or rectum that are small (≤ 1 cm) and well differentiated can be considered “early” tumors, since they generally have a (very) good prognosis. In the new WHO classification of 2010, these neoplasms are called neuroendocrine tumors/ carcinoids (NETs), grade (G) 1 or 2, and distinguished from poorly differentiated neuroendocrine carcinomas (NECs), G3. NETs are increasing, with a rise in the age-adjusted incidence in the U.S.A. by about 700 % in the last 35 years. Improved early detection seems to be the main reason for these epidemiological changes. Both the better general availability of endoscopy, and imaging techniques, have led to a shift in the discovery of smaller-sized (≤ 10-20 mm) intestinal NETs/carcinoids and earlier tumor stages at diagnosis. Endoscopic screening is therefore effective in the early diagnosis, not only of colorectal adenocarcinomas, but also of NETs/carcinoids. Endoscopic removal, followed up with endoscopic surveillance is the treatment of choice in NETs/carcinoids of the stomach, duodenum and rectum that are ≤ 10 mm in size, have a low proliferative activity (G1), do not infiltrate the muscular layer and show no angioinvasion. In all the other intestinal NENs, optimal treatment generally needs surgery and/or medical therapy depending on type, biology and stage of the tumor, as well as the individual situation of the patient.