Septic appendicitis with perforation, large omental torsion, and septic appendiceal fatty pendicitis are rare clinically and can all present with fixed pressure pain and varying degrees of rebound pain in the right lower abdomen and elevated leukocyte and neutrophil classification, and are easily misdiagnosed clinically as acute appendicitis. A total of 10 cases of the above pathology confirmed by pathology (except for spontaneous bleeding from ovarian veins without specimen) were admitted to our hospital from January 2005 to February 2012, and are retrospectively summarized and analyzed as follows. 1 Clinical data 1. 1 General information There were 10 cases in this group, including 3 males and 7 females, aged 23-67 years, with an average of 36. 3 years; 4 cases of septic appendicitis with perforation, 3 cases of large omental torsion, and 3 cases of septic appendiceal fatty pendicitis. All cases had varying degrees of right lower abdominal fixed pressure pain and rebound pain, and elevated leukocytes and neutrophil classification. All patients were misdiagnosed as acute appendicitis and operated on urgently. 1. 2 Treatment One case of septic appendicitis with perforation, three cases of large omental torsion, and one case of septic appendicitis in the fatty pendant of the cecum were found during laparoscopic appendectomy with a normal appendix and were treated with laparoscopic ileocecal resection, necrotic fatty pendant resection, and necrotic large omental resection, respectively. In the remaining 5 cases, the appendix was found to be normal or slightly congested intraoperatively, and the extended incisional exploration revealed parallel ileal resection and necrotic fat pendant resection. 2 Results Among the 10 patients, one case of postoperative incisional infection occurred, and there were no fatal cases. All cases were followed up for 1 year, 1 case of inflammatory granuloma in the right lower abdomen, and the rest of the patients had good diet, stool and life and work. 3 Discussion Acute appendicitis is a common acute abdominal disease in general surgery, and its diagnosis is relatively simple, and the preoperative examination is usually limited to routine blood and abdominal ultrasound, etc. Once the patient is diagnosed as “acute appendicitis” by the outpatient or emergency physician and admitted to the hospital, the inpatient physician is the first to do a simple medical history and physical examination (1), and then add the metastatic right lower abdominal pain, right lower abdominal fixed granuloma, and right lower abdominal pain. The inpatient physician is preoccupied with a simple history and physical examination (1), and with the usual thinking that metastatic right lower abdominal pain, fixed pressure pain in the right lower abdomen with varying degrees of rebound pain and elevated leukocytes are the gold standard for the diagnosis of acute appendicitis, there is still a certain percentage of clinical misdiagnosis (2). However, most of the literature reports other common conditions in the right lower abdomen such as: pelvic inflammatory disease and adnexitis, ovarian cystic torsion, ileal tumor, perforated gastroduodenal ulcer, ureteral stone, etc (2,3). Rarely, septic appendicitis with perforation of the cecum, septic appendicitis of the fatty pendulum of the cecum, and infarction of the greater omentum have been reported in the literature. Appendicitis was first identified in cases of leukopenia during chemotherapy in patients with leukemia, and later in patients with malignancy and immunocompromised and rheumatic diseases (4,5). The exact etiological mechanism is not known and it is generally believed that there is no significant difference in the incidence between men and women. The typical clinical manifestations are: right lower abdominal pain and fever, which may be accompanied by nausea, vomiting and diarrhea (may be bloody stools). On physical examination, there are obvious pressure pain and rebound pain in the right lower abdomen. Because the symptoms and signs resemble acute appendicitis, it is often misdiagnosed as acute appendicitis and operated on. The appendix is often misdiagnosed as acute appendicitis and operated on. Most of the intraoperative findings are cecum edema or masses, and in severe cases, necrosis and perforation, abscess formation, etc. The lesions may also involve the ileum, but the appendix is not abnormal. The disease has been named granulocytopenic enteritis, necrotizing enterocolitis and ileocecal syndrome. Since most of this disease is found during appendicitis surgery and is mostly misdiagnosed as tumor and Crohn’s disease intraoperatively, the treatment is surgical. The current literature reports surgical treatment as the main methods of surgical treatment: right hemicolectomy and terminal ileostomy (4,6). In this paper, all four patients had lesions limited to the cecum, and all of them were diagnosed with diverticulitis and perforation of the cecum intraoperatively, and none of them was considered to be cecum, so all of them underwent ileocolic resection, and there were no other complications after surgery except for one patient (scarred body) who developed inflammatory granuloma in the right lower abdomen, suggesting that ileocolic resection is also one of the methods. Primary torsion of the greater omentum refers to torsion without obvious pathological factors, which may be caused by anatomical variation of the greater omentum, such as hypertrophy of the greater omentum, long tongue protrusion, bifurcation of the omentum, etc. Secondary torsion of the greater omentum is often caused by tumors or cysts of the greater omentum, inflammatory lesions of the abdominal cavity, abdominal adhesions, adhesions of the hernia sac, etc. The lesions are usually found intraoperatively. The incidence of greater omental torsion is low, with no specific clinical manifestations or abdominal signs, and no specific medical examination methods or imaging features, so the preoperative diagnosis rate is low and easily misdiagnosed. Due to the long right greater omentum, it is prone to torsion. In the early stage of the disease, the root of the greater omentum is stretched, the blood vessels are strangulated and the vegetative nerves are stimulated, manifesting as periumbilical or subxiphoid pain, and in the later stage, due to the bruising and necrosis of the distal greater omentum of torsion, the local abdominal wall where the greater omentum is located is stimulated to cause pain, resulting in typical metastatic right lower abdominal pain. Therefore, the majority of large omental torsions are misdiagnosed as acute appendicitis (8). We have reported four cases of large omental torsion (9), three of which were misdiagnosed as acute appendicitis and underwent laparoscopic large omental resection, and were discharged 3-5 d after surgery with no special discomfort in the six-month postoperative follow-up. Fatty pituitary suppurative inflammation is much rarer clinically, and no literature has been seen on its natural course, but it is speculated that the mechanism is no more than mechanical torsion, venous embolism, and possible hematogenous infection.