Is appendoscope a new option for the treatment of acute appendicitis?

Acute appendicitis is a common surgical emergency.It is commonly caused by obstruction of the appendiceal lumen due to fecaliths,tumors,or lymphoid hyperplasia.For over a century,appendectomy has been the primary treatment for acute appendicitis.Abraham Groves performed the first open appendectomy in 1883.In 1983,Kurt Semm completed the first laparoscopic appendectomy,heralding a new era in appendectomy.However,appendectomy is associated with certain complications and a rate of negative appendectomies.Studies have suggested controversy over the impact of appendectomy on the development of inflammatory bowel disease and Parkinson’s disease,but an increasing number of studies indicate a possible positive correlation between appendectomy and colorectal cancer,gallstones,and cardiovascular disease.With the recognition that the appendix is not a vestigial organ and the advancement of endoscopic technology,Liu proposed the endoscopic retrograde appendicitis therapy.It is an effective minimally invasive alternative for treating uncomplicated acute appendicitis.Our team has developed an appendoscope with a disposable digital imaging system operated through the biopsy channel of a colonoscope and successfully applied it in the treatment of appendicitis.This article provides an overview of the progress in endoscopic treatment for acute appendicitis and offers a new perspective on the future direction of appendiceal disease treatment.

Influence of sarcopenia and frailty in the management of elderly patients with acute appendicitis

In developed countries,the average life expectancy has been increasing and is now well over 80 years.Increased life expectancy is associated with an increased number of emergency surgical procedures performed in later age groups.Acute appendicitis is one of the most common surgical diseases,with a lifetime risk of 8%.A growing incidence of acute appendicitis has been registered in the elderly population and in the oldest groups(>80 years).Among patients>50-year-old who present to the emergency department for acute abdominal pain,15%have acute appendicitis.In these patients,emergency surgery for acute appendicitis is challenging,and some important aspects must be considered.In the elderly,surgical treatment outcomes are influenced by sarcopenia.Sarcopenia must be considered a precursor of frailty,a risk factor for physical function decline.Sarcopenia has a negative impact on both elective and emergency surgery regarding mortality and morbidity.Aside from morbidity and mortality,the most crucial outcomes for older patients requiring emergency surgery are reduction in function decline and preoperative physical function maintenance.Therefore,prediction of function decline is critical.In emergency surgery,preoperative interventions are difficult to implement because of the narrow time window before surgery.In this editorial,we highlight the unique aspects of acute appendicitis in elderly patients and the influence of sarcopenia and frailty on the results of surgical treatment.

Added value of ratio of cross diameters of the appendix in ultrasound diagnosis of acute appendicitis

BACKGROUND The maximum outer diameter(MOD)of the appendix is an essential parameter for diagnosing acute appendicitis,but there is space for improvement in ultrasound(US)diagnostic performance.AIM To investigate whether combining the ratio of the cross diameters(RATIO)of the appendix with MOD of the appendix can enhance the diagnostic performance of acute appendicitis.METHODS A retrospective study was conducted,and medical records of 233 patients with acute appendicitis and 112 patients with a normal appendix were reviewed.The MOD and RATIO of the appendix were calculated and tested for their diagnostic performance of acute appendicitis,both individually and in combination.RESULTS The RATIO for a normal appendix was 1.32±0.16,while for acute appendicitis it was 1.09±0.07.The cut-off value for RATIO was determined to be≤1.18.The area under the receiver operating characteristic curve(AUC)for diagnosing acute appendicitis using RATIO≤1.18 and MOD>6 mm was 0.870 and 0.652,respectively.There was a significant difference in AUC between RATIO≤1.18 and MOD>6 mm(P<0.0001).When comparing the combination of RATIO≤1.18 and MOD>6 mm with MOD>6 mm alone,the combination showed increased specificity,positive predictive value(PPV),and AUC.However,the sensitivity and negative predictive value decreased.CONCLUSION Combining RATIO of the appendix≤1.18 and MOD>6 mm can significantly improve the specificity,PPV,and AUC in the US diagnosis of acute appendicitis.

Evaluation of the clinical effects of atropine in combination with remifentanil in children undergoing surgery for acute appendicitis

BACKGROUND Acute appendicitis(AA)is the most common cause of acute abdomen in children.Anesthesia significantly influences the surgical treatment of AA in children,making the scientific and effective selection of anesthetics crucial.AIM To assess the clinical effect of atropine(ATR)in combination with remifentanil(REMI)in children undergoing surgery for AA.METHODS In total,108 cases of pediatric AA treated between May 2020 and May 2023 were selected,58 of which received ATR+REMI[research group(RG)]and 50 who received REMI[control group(CG)].Comparative analyses were conducted on the time to loss of eyelash reflex,pain resolution time,recovery time from anesthesia,incidence of adverse events(AEs;respiratory depression,hypoxemia,bradycardia,nausea and vomiting,and hypotension),intraoperative responses(head shaking,limb activity,orientation recovery,safe departure time from the operating room),hemodynamic parameters[oxygen saturation(SPO2),mean arterial pressure,heart rate,and respiratory rate],postoperative sedation score(Ramsay score),and pain level[the Face,Legs,Activity,Cry,Consolability(FLACC)Behavioral Scale].RESULTS Compared with the CG,the RG showed significantly shorter time to loss of eyelash reflex,pain resolution,recovery from anesthesia,and safe departure from the operating room.Furthermore,the incidence rates of overall AEs(head shaking,limb activity,etc.)were lower,and influences on intraoperative hemodynamic parameters and stress response indexes were fewer.The Ramsay score at 30 min after extubation and the FLACC score at 60 min after extubation were significantly lower in the RG than in the CG.CONCLUSION ATR+REMI is superior to REMI alone in children undergoing AA surgery,with a lower incidence of AEs,fewer influences on hemodynamics and stress responses,and better post-anesthesia recovery.

Indication of conservative treatment by antibiotics for uncomplicated and complicated acute appendicitis

BACKGROUND Acute appendicitis is one of the most common emergency abdominal disease,and recent studies have evaluated conservative treatment using antibiotics for uncomplicated appendicitis.Although the efficacy of conservative treatment for uncomplicated appendicitis is known,its efficacy for complicated appendicitis remains unknown,so are risk factors for the conservative treatment of appendi-citis.In our institution,conservative treatment has long been the first choice for most appendicitis cases,except for perforation.Therefore,this novel study inves-tigated the outcomes of conservative treatment for uncomplicated and compli-cated acute appendicitis and the risk factors associated with conservative treat-ment.treatment.The significant and independent predictors of resistance to conservative treatment were body temperature≥37.3℃,appendicolith and Douglas sinus fluid visible on computed tomography(CT).The rate of resistance to conservative treatment was 66.7%(6/9)for patients with the above three factors,22.9%(8/35)for patients with two factors(appendicolith and body temperature≥37.3℃),16.7%(2/12)for patients with two factors(Douglas sinus fluid and appendicolith)and 11.1%(1/9)for patients with two factors(Douglas sinus fluid and body temperature≥37.3℃).CONCLUSION A temperature≥37.3℃,appendicolith and Douglas sinus fluid on CT might be clinical risk factors of resistance to conservative treatment for acute appendicitis.

Laparoscopic appendectomy for acute appendicitis: How to discourage surgeons using inadequate therapy

Acute appendicitis(AA) develops in a progressive and irreversible manner, even if the clinical course of AA can be temporarily modified by intentional medications. Reliable and real-time diagnosis of AA can be made based on findings of the white blood cell count and enhanced computed tomography. Emergent laparoscopic appendectomy(LA) is considered as the first therapeutic choice for AA. Interval/delayed appendectomy at 6-12 wk after disease onset is considered as unsafe with a high recurrent rate during the waiting time. However, this technique may have some advantages for avoiding unnecessary extended resection in patients with an appendiceal mass. Nonoperative management of AA may be tolerated only in children. Postoperative complications increase according to the patient's factors, and temporal avoidance of emergent general anesthesia may be beneficial for high-risk patients. The surgeon's skill and cooperation of the hospital are important for successful LA. Delaying appendectomy for less than 24 h from diagnosis is safe. Additionally, a semi-elective manner(i.e., LA within 24 h after onset of symptoms) may be paradoxically acceptable, according to the factors of the patient, physician, and institution. Prompt LA is mandatory for AA. Fortunately, the Japanese government uses a universal health insurance system, which covers LA.

Septic thrombophlebitis of the porto-mesenteric veins as a complication of acute appendicitis

Pylephlebitis, a rare complication of acute appendicitis, is defined as thrombophlebitis of the portal venous system. Pylephlebitis usually occurs due to secondary infection in the region drained into the portal system. We report a case of pylephlebitis caused by acute appendicitis. The patient was transferred from a private clinic 1 wk after appendectomy with the chief complaints of high fever and abdominal pain. He was diagnosed with pylephlebitis of the portal vein and superior mesenteric vein by CT-scan. The patient was treated with antibiotics and anticoagulation therapy, and discharged on the 25th day and follow-up CT scan showed a cavernous transformation of portal thrombosis.

Seasonal variations of acute appendicitis and nonspecific abdominal pain in Finland

AIM: To investigate whether seasonal changes had an effect on the incidence of acute appendicitis (AA) or nonspecific abdominal pain (NSAP).

Revisiting delayed appendectomy in patients with acute appendicitis

Acute appendicitis(AA)is the most common acute abdomen,and appendectomy is the most common nonelective surgery performed worldwide.Despite the long history of understanding this disease and enhancements to medical care,many challenges remain in the diagnosis and treatment of AA.One of these challenges is the timing of appendectomy.In recent decades,extensive studies focused on this topic have been conducted,but there have been no conclusive answers.From the onset of symptoms to appendectomy,many factors can cause delay in the surgical intervention.Some are inevitable,and some can be modified and improved.The favorable and unfavorable results of these factors vary according to different situations.The purpose of this review is to discuss the causes of appendectomy delay and its risk-related costs.This review also explores strategies to balance the positive and negative effects of delayed appendectomy.

Acute appendicitis complicated by mesenteric vein thrombosis: A case report

BACKGROUND Acute appendicitis with mesenteric vein thrombosis(MVT)is an uncommon condition and usually lacks specific clinical manifestations,which leads to a high rate of misdiagnosis or delayed diagnosis,especially when it is accompanied by other abdominal diseases.Prompt and accurate recognition is vital for treatment and prognosis.CASE SUMMARY A 37-year-old woman had a history of acute metastatic right lower abdominal pain,nausea,and fever.A contrast-enhanced computed tomography(CT)scan showed a filling defect in the mesenteric vessels.The patient was diagnosed with acute appendicitis complicated by MVT and was treated with anticoagulation and intravenous antibiotics.The follow-up CT scan showed full resolution of the thrombosis and inflammation.CONCLUSION Clinical awareness is essential for recognizing MVT,especially when it is accompanied by other common acute abdominal diseases,such as acute appendicitis.Contrast-enhanced CT is helpful for the diagnosis of MVT and is recommended for patients with acute abdominal diseases.

Endoscopic treatment for acute appendicitis with coexistent acute pancreatitis: Two case reports

BACKGROUND Appendectomy is the procedure of choice for the treatment of acute appendicitis.However,surgery may not be appropriate for patients with coexisting severe illness or comorbidities such as acute pancreatitis(AP).Endoscopic retrograde appendicitis treatment(ERAT)may be a novel alternative to surgery for treating such patients where existing medical therapies have failed.CASE SUMMARY We report 2 cases of moderately severe AP who developed acute uncomplicated appendicitis during their hospital stay and did not respond to traditional medical therapy.One patient had moderately severe AP due to hyperlipidemia,while the other patient had a gallstone induced by moderately severe AP.Neither patient was fit to undergo an appendectomy procedure because of the concurrent AP.Therefore,the alternative and minimally invasive ERAT was considered.After written informed consent was collected from the patients,the ERAT procedure was performed.Both patients exhibited fast postoperative recovery after ERAT with minimal surgical trauma.CONCLUSION ERAT is a safe and effective minimally invasive endoscopic procedure for acute appendicitis in patients with coexistent AP.

Acute appendicitis in the short term following radical total gastrectomy misdiagnosed as duodenal stump leakage:A case report

BACKGROUND Common diseases after radical gastrectomy include cholecystitis and pancreatitis,but the sudden onset of acute appendicitis in a short period following radical gastrectomy is very rare,and its clinical symptoms are easily misdiagnosed as duodenal stump leakage.CASE SUMMARY This is a case report of a 77-year-old woman with lower right abdominal pain 14 d after radical resection of gastric cancer.Her pain was not relieved by conservative treatment,and her inflammatory markers were elevated.Computed tomography showed effusion in the perihepatic and hepatorenal spaces,right paracolic sulcus and pelvis,as well as exudative changes in the right iliac fossa.Ultrasoundguided puncture revealed a slightly turbid yellow-green fluid.Laparoscopic exploration showed a swollen appendix with surrounding pus moss and no abnormalities of the digestive anastomosis or stump;thus,laparoscopic appendectomy was performed.The patient recovered well after the operation.Postoperative pathology showed acute purulent appendicitis.The patient continued adjuvant chemotherapy after surgery,completing three cycles of oxaliplatin plus S-1(SOX regimen).CONCLUSION Acute appendicitis in the short term after radical gastrectomy needs to be differentiated from duodenal stump leakage,and early diagnosis and surgery are the most important means of treatment.

Imaging of acute appendicitis: Advances

We read with interest the review by Teng et al,who summarized the current approach to the diagnosis and treatment of acute appendicitis(AA).Also,the article summarizes the clinical scoring systems very effectively.In one of the previous studies conducted by our research group,we showed that the use of the Alvarado score,ultrasound and C-reactive protein values in combination provides a safe confirmation or exclusion of the diagnosis of AA.Computed tomography is particularly sensitive in detecting periappendiceal abscess,peritonitis and gangrenous changes.Computed tomography is not a good diagnostic tool in pediatric patients because of the ionizing radiation it produces.Ultrasound is a valuable diagnostic tool to differentiate AA from lymphoid hyperplasia.Presence of fluid collection in the periappendiceal and lamina propria thickness less than 1 mm are the most effective parameters in differentiating appendicitis from lymphoid hyperplasia.Although AA is the most common cause of surgical acute abdomen,it remains an important diagnostic and clinical challenge.By combining clinical scoring systems,laboratory data and appropriate imaging methods,diagnostic accuracy and adherence to treatment can be increased.Lymphoid hyperplasia and perforated appendicitis present significant diagnostic challenges in children.Additional ultrasound findings are increasingly defined to differentiate AA from these conditions.

Acute Appendicitis Pathways: A Systemic Review

Background: Clinical pathways are effective in reducing healthcare cost and standardizing management protocol for diseases and conditions. However, there are no standardized pathways for appendicitis. This study aims to determine whether implementation of a standardized clinical pathway for managing appendicitis may lead to improved patient care. Materials and Methods: We searched for articles published in PubMed, MEDLINE, and Cochrane library between 1974 and 2015. Thirty-seven papers published in English that met inclusion criteria were included and analyzed in this review. A total of 37 studies met inclusion criteria and were analyzed for the purpose of this study. Results: A clear definition for appendicitis pathway was observed in 30 articles. Appendicitis was diagnosed based on clinical and laboratory findings;however, 34% of the studies included radiological investigations. Sixteen studies provided clear definitions for discharge criteria. Time of follow-up (5 - 28 days) was reported in 10 studies. Operative time was the most commonly used outcome measure. The mean length of stay for non-complicated appendicitis was 1.3 days, and 6.26 days for complicated appendicitis. Most of the studies concluded that the accuracy of a clinical pathway for appendicitis diagnosis can be achieved by assessing the incidence of a normal appendix. The mean cost for patient care was $4874.14 (SAR 18,278.03). Conclusion: There was no standardized definition for appendicitis clinical pathway components. Studies suggested that establishing a clinical pathway for appendicitis improves the outcome and minimizes the cost.

Diagnosis of Acute Appendicitis in Adults: Role of a Simple Clinical Diagnostic Triad

Objectives: Acute appendicitis remains the commonest intra-abdominal surgical emergency. This study sought to identify the clinical factors that are most reliable in the diagnosis of acute appendicitis. Methods: This was a retrospective review of consecutive adult appendicectomies over a 6 months period. The frequency of different clinical parameters was assessed to determine the most reliable predictors of acute appendicitis. A simple triad of 3 of the most frequent clinical parameters was examined for diagnostic potential by calculating its sensitivity, specificity, positive predictive value and negative predictive value. Results: There were a total of 124 patients. The median age was 33 years while the gender distribution was 54 males to 70 females. The most common clinical parameters in the patients with appendicitis were right iliac fossa tenderness or peritonism (100.0%), anorexia (78.8%), nausea (75.9%), migratory abdominal pain i.e. pain migrating to right lower quadrant (55.7%), tachycardia (41.3%) and pyrexia i.e. body temperature of 37.8 degrees Celsius and above (22.1%). The simple triad of anorexia, right iliac fossa tenderness and migratory abdominal pain showed specificity for the diagnosis of acute appendicitis of 84.2% and sensitivity of 45.7%. The positive predictive value of this triad was 94.1% while the negative predictive value was 21.9%. Conclusion: Our study reveals that the positivity for this simple clinical triad strongly rules in the diagnosis of acute appendicitis. Its specificity and positive predictive value compares with the most reliable scoring systems for acute appendicitis in literature. Further approaches to diagnosis such as imaging and diagnostic laparoscopy should be considered when this triad is negative and appendicitis is suspected. This simple diagnostic approach allows for prompt diagnosis and treatment which expectedly would improve the morbidity associated with acute appendicitis.

Acute appendicitis presenting with abdominal wall and right groin abscess:A case report

We report a case of right lower abdominal wall and groin abscess resulting from acute appendicitis. The patient was an 27-year-old man who had no apparent abdominal signs and was brought to the hospital due to progressive painful swelling of right lower abdomen and the groin for 10 d. Significant inflammatory changes of soft tissue involving the right lower trunk were noted without any apparent signs of peritonitis. Laboratory results revealed leukocytosis. Abdominal ultrasonography described the presence of abscess at right inguinal site also communicating with the intraabdominal region. Right inguinal exploration and laparotomy were performed and about 250 mL of pus was drained from the subcutaneous tissue and preperitoneal space. No collection of pus was found intraabdominally and subserous acute appendicitis was the cause of the abscess. The patient fully recovered at the end of the second post-operation week. This case reminds us that acute appendicitis may have an atypical clinical presentation and should be treated carefully on an emergency basis to avoid serious complications.

Managing acute appendicitis during the COVID-19 pandemic in Jiaxing, China

BACKGROUND Coronavirus disease 19(COVID-19)is a global pandemic and has had a profound impact on our routine surgical activities.Acute appendicitis is the most common abdominal emergency worldwide.Therefore,it is highly essential to assess the influence the pandemic has on acute appendicitis.AIM To assess the efficacy of the management of acute appendicitis during the COVID-19 pandemic.METHODS We retrospectively analyzed 90 patients who presented with acute appendicitis during the outbreak of COVID-19 in Jiaxing,China.Clinical data regarding appendectomies patients were also collected for the corresponding time frame from 2019.Preoperative management,intraoperative protective measures,and postoperative management were conducted.RESULTS After screening,six patients were identified as unqualified due to fever and were then referred to the COVID-19 expert group.The results of the nucleic acid test were negative.Of the 76 patients enrolled in the simple group,nine patients received medication therapy,and all others underwent surgery.From this same group,66 patients were diagnosed with suppurative appendicitis,and one patient was diagnosed with perforated appendicitis after surgery.There were 14 patients in the complex group,for which the postoperative diagnosis indicated perforated appendicitis.The proportion of men with perforated appendicitis was higher than that in 2019(P<0.05).The chief complaint duration for perforated appendicitis patients in 2020 was longer than that in 2019(P<0.05).The routine blood test showed that white blood cell counts and neutrophil ratios were higher in perforated appendicitis patients in 2020 than in 2019(P<0.05).The ratio of open appendectomies to the amount of mean blood loss during surgery was greater in 2020 than in 2019(P<0.05).Online consultation after discharge was selected in 59 cases(65.6%).No perioperative infection with COVID-19 or long-term postoperative complications were found.CONCLUSION The management of acute appendicitis from Jiaxing effectively reduced the influence of the pandemic and minimized the risk of nosocomial infection.

COVID-19 pandemic changed the management and outcomes of acute appendicitis in northern Beijing:A single-center study

BACKGROUND Since the outbreak of the coronavirus disease 2019(COVID-19)pandemic,outcomes and management of many diseases have been affected.Acute appendicitis is a common acute abdomen.The incidence rate is 0.05%-0.5%.Studies reported that the number of patients with appendicitis admitted to emergency department significantly decreased since the pandemic.People avoided going to the hospital for fear of being infected.Different countries have different epidemic prevention measures that result in different treatment outcomes.The Chinese government also published some temporary measures in order to prevent the outbreak.AIM To explore the changes in management and outcomes of acute appendicitis during the COVID-19 pandemic in the North of Beijing.METHODS Patients with acute appendicitis admitted to Beijing Tsinghua Changgung Hospital between February and June 2019 and February and June 2020 were retrospectively reviewed.Cases were grouped according to admission year.The demographic characteristics,present illnesses,medical history,symptoms and signs,comorbidities,blood test results,imaging data,appendix pathology,and treatment details were compared.RESULTS Overall,74 patients received nonsurgical treatment and 113 patients underwent surgical treatment in group 2019,whereas 159 patients received nonsurgical treatment and 26 patients received surgical treatment in group 2020.Fever,thick appendix,nonsurgical management,and uncomplicated appendicitis(simple or supportive appendicitis)were more common in group 2020(P<0.05).Among the nonsurgical management cases,the neutrophil percentage,neutrophil-tolymphocyte ratio,and recurrence rate were higher in group 2020(P<0.05).Among surgically managed cases,there were more cases with gastrointestinal symptoms,peritonitis,ascites in the image,and intraoperative adhesion or ascites in group 2020(P<0.05).The white blood cell count,time from diagnosis to surgery,surgical time,and intraoperative blood loss were higher in group 2020(P<0.05).CONCLUSION During the COVID-19 pandemic,patients suffering from acute appendicitis in Beijing tended to present with severe symptoms and opt for nonsurgical treatment.For patients who underwent surgical management,the operation was delayed and more difficult during the pandemic.Nevertheless,the hospital stay and the incidence of postsurgical complications did not change.

Effect of the COVID-19 pandemic on patients with presumed diagnosis of acute appendicitis

BACKGROUND Acute appendicitis(AAp) is the most frequent cause of acute abdominal pain,and appendectomy is the most frequent emergency procedure that is performed worldwide.The coronavirus disease 2019(COVID-19) pandemic has caused delays in managing diseases requiring emergency approaches such as AAp and trauma.AIM To compare the demographic,clinical,and histopathological outcomes of patients with AAp who underwent appendectomy during pre-COVID-19 and COVID-19 periods.METHODS The demographic,clinical,biochemical,and histopathological parameters were evaluated and compared in patients who underwent appendectomy with the presumed diagnosis of AAp in the pre-COVID-19(October 2018-March 2020) and COVID-19(March 2020-July 2021) periods.RESULTS Admissions to our tertiary care hospital for AAp increased 44.8% in the COVID-19 period.PreCOVID-19(n = 154) and COVID-19(n = 223) periods were compared for various parameters,and we found that there were statistically significant differences in terms of variables such as procedures performed on the weekdays or weekends [odds ratio(OR):1.76;P = 0.018],presence of AAp findings on ultrasonography(OR:15.4;P < 0.001),confirmation of AAp in the histopathologic analysis(OR:2.6;P = 0.003),determination of perforation in the appendectomy specimen(OR:2.2;P = 0.004),the diameter of the appendix(P < 0.001),and hospital stay(P = 0.003).There was no statistically significant difference in terms of interval between the initiation of symptoms and admission to the hospital between the pre-COVID-19(median:24 h;interquartile range:34) and COVID-19(median:36 h;interquartile range:60) periods(P = 0.348).The interval between the initiation of symptoms until the hospital admission was significantly longer in patients with perforated AAp regardless of the COVID-19 or pre-COVID-19 status(P < 0.001).CONCLUSION The present study showed that in the COVID-19 period,the ultrasonographic determination rate of AAp,perforation rate of AAp,and duration of hospital stay increased.On the other hand,negative appendectomy rate decreased.There was no statistically significant delay in hospital admissions that would delay the diagnosis of AAp in the COVID-19 period.

Extraintestinal heterotopic gastric tissue simulating acute appendicitis

We describe the case of a 68-year-old otherwise healthy male who presented to our emergency room with signs and symptoms of acute appendicitis. Exploratory surgery revealed a normal appendix. Further examination revealed an enlarged lymph node-like mass of tissue near the appendix, in the ileocecal mesentery. This mass was removed and was found to be inflamed heterotopic gastric tissue. Although reports of heterotopic gastric tissue in the literature are common, we believe that this case represents the first report of inflamed heterotopic gastric tissue simulating appendicitis.