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Several neoplastic and non-neoplastic proliferations of the appendix can show varying degrees of serrated epithelial architecture. Of these, diffuse mucosal hyperplasia is most common, followed in frequency by low-grade mucinous and serrated neoplasms. It is important to distinguish serrated appendiceal neoplasms from their potential mimics because these entities may be managed differently. Diffuse mucosal hyperplasia is a non-neoplastic change that usually develops in the setting of resolving appendicitis and requires no further therapy or surveillance, and serrated neoplasms confined to the mucosa are adequately treated by appendectomy alone. On the other hand, low-grade appendiceal mucinous neoplasms may require surveillance, and those with extra-appendiceal spread differ from adenocarcinomas arising from serrated neoplasms with respect to both treatment and prognosis. Low-grade mucinous neoplasms in the peritoneum are frequently amenable to peritoneum-directed therapies alone, while adenocarcinomas derived from serrated neoplasms often spread to both regional lymph nodes and the peritoneum, potentially requiring right colectomy and systemic chemotherapy. The purpose of this review is to summarize the literature regarding the clinical and pathologic features of appendiceal lesions that show epithelial serration and provide the reader with helpful tips to distinguish serrated neoplasms from their mimics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Objective: Appendiceal mucinous tumors can be encountered in four different types. The clinical approach varies according to these types and the severity of the present disease. We aimed to share clinical, radiological, and pathological features and surgical options of the patients diagnosed with mucinous tumors at our center. Material and Methods: Between August 2009 and March 2016, 757 patients underwent appendectomy for presumed diagnosis of acute appendicitis at the Department of Surgery, Kahramanmaraş Sütçü İmam University School of Medicine, Kahramanmaraş, Turkey. Among them, demographic, clinical, and histopathological characteristics of patients who diagnosed with appendiceal mucinous tumors were retrospectively analyzed. This study was approved by our faculty's human ethics committee. Results: Incidence of mucinous tumor was 1.71%. Mean age of a total of 13 cases including 6 women and 7 men was 52.4±21.6 years (Range: 25-83 years). On preoperative diagnosis, acute appendicitis was detected in 8 patients, perforated appendicitis and periappendiceal abscess in two patients, and suspicious cecal mass in two patients. One patient had an operation for uterine leiomyoma. On histopathological examination, four patients were diagnosed with simple mucinous cyst, four with mucinous cystadenoma, three with mucosal hyperplasia, and two with mucinous cystadenocarcinoma. Mean duration of hospital stay was 5.1±4.7 days. One patient died from septic shock on first day, one from respiratory failure on 14th day, and one from cardiac arrest on 20th day. The average follow-up duration for the other 10 patients was 44 months (ranging from 1 to 78 months). No recurrence or death occurred in these patients over the course of follow-up. Conclusion: Intraoperative clinical diagnosis of appendiceal mucinous tumors is rarely seen. Close histopathological and cytological examination of the specimen is required to separate malignant tumors from benign ones. The treatment varies depending on different types and the severity of the disease. [ABSTRACT FROM AUTHOR]

A major aspect of pathology in otitis media (OM), the most common childhood bacterial disease, is hyperplasia of the middle ear mucosa. Activation of innate immune receptors during OM leads to the activation of NF-κB, a pleiotropic transcription factor involved both in inflammation and tissue growth. To explore the role of NF-κB in mucosal hyperplasia during OM, we evaluated the expression of genes involved in two modes of NF-κB activation during a complete episode of acute, bacterial OM in mice. We also determined the effects of inhibitors of each pathway on infection-stimulated mucosal growth in vitro. A majority of the genes that mediate both the canonical and the non-canonical pathways of NF-κB activation were regulated during OM, many with kinetics related to the time course of mucosal hyperplasia. Inhibition of either pathway reduced the growth of cultured mucosal explants in a dose-dependent manner. However, inhibition of the canonical pathway produced a greater effect, suggesting that this mode of NF-κB activation dominates mucosal hyperplasia during OM. [ABSTRACT FROM AUTHOR]

Abstract: Administration of an iron-deficient diet to Wistar rats resulted within 14 days in reduced serum iron concentrations, a microcytic hypochromic anemia, characteristic for impaired hemoglobin synthesis, and an increase of duodenal epithelial cell proliferation. After 5 weeks of iron deficiency, hypochromic microcytic anemia and a clear increase of duodenum weight but no pronounced effects on cell proliferation was observed. Increased duodenum weights corresponded to significant increases in mucosal area, indicating a diffuse, simple mucosal hyperplasia. The sequence of events following iron depletion thus appears to be: (1) reduced serum iron levels, (2) induction of hypochromic microcytic anemia, (3) increased duodenal epithelial cell proliferation, and (4) increased duodenal weight (increased mucosal area). Iron deficiency anemia was rapidly reversible after a 2-week recovery period. However, increased duodenum weights were still noted at that time. Intramuscular iron supplementation in animals fed with iron-deficient diet maintained body iron levels not below normal values, and neither anemia nor increased duodenum cell proliferation were detected after 14 days. A 5-week iron supplementation period resulted in slightly increased serum iron values, and slightly decreased duodenal epithelial cell proliferation. Thus, increased duodenum mucosal hyperplasia was shown to be secondary to depletion of body iron and anemia and reflects an attempt to increase iron absorption to counteract iron deficiency. [Copyright &y& Elsevier]

Summary: Epithelial tumours of the appendix include low-grade mucosal-based tumours with an excellent prognosis as well as invasive carcinomas that are frequently fatal. Low-grade mucinous neoplasms spread to the peritoneum as pseudomyxoma peritonei, and the nomenclature of these tumours has been the subject of considerable disagreement among pathologists. Invasive adenocarcinomas are more often mucinous than colorectal carcinoma and may also spread to the peritoneum. These tumours also lack uniform terminology. In this article, the clinical and pathologic features of low-grade appendiceal mucinous tumours and appendiceal adenocarcinomas are reviewed. In addition, serrated polyps and serrated adenomas, whose significance in the colon is only beginning to be understood, are considered in the appendix. Retention cysts, hyperplastic polyps, and diffuse mucosal hyperplasia, although not truly neoplastic, are reviewed here as they may enter into the differential diagnosis of appendiceal mucinous neoplasms. [Copyright &y& Elsevier]

Eighteen patients with recurrent benign biliary strictures (BBS) were selected for metallic stents placement because they failed to respond to percutaneous balloon dilatation. None were candidates for surgical corrections. We used "Z" single or double stents in 17 cases and a Wallstent in 1 case. After more than 3 years of follow-up (average period 37 months, range 30-41 months), 10 patients (55.5%) were asymptomatic without signs of bile stasis; 5 patients (27.7%) had recurrence of symptoms and were eventually retreated; and 3 patients (16.6%) died, 2 of obstructive jaundice and liver failure and 1 of metastatic gastric cancer. Recurrence was due to stent occlusion by tissue ingrowth in 3 cases, stent migration in 1 case, and an inflammatory lesion of the papilla of Vater in another case, with patency of the metallic stent. The overall patency rate, at 3-year follow-up was 68.7%. In our series, the main factor determining long-term patency of metallic stents has been reactive tissue ingrowth. Nevertheless, long-term results obtained with metallic stents in recurrent benign biliary strictures should be considered satisfactory. In selected patients, metallic stents may represent the only long-term treatment available for maintaining bile flow. [ABSTRACT FROM AUTHOR]

We evaluated the effect of zinc deficiency on the development of mucosal hyperplasia in male Sprague-Dawley rats following 70% small-bowel resection: 20 underwent 70% jejunoileal resection, another 20 were sham operated. Half of each group were made zinc deficient by force-feeding technique. Operations were then performed, and feedings were continued for another 9 days. While mucosal weight did not differ between zinc-deficient and zinc-replete animals, whether or not they underwent resection, mucosal protein and DNA levels were decreased in both resected and sham-operated, zinc-deficient animals. Functional indices were also affected. Maltase activities were decreased in zinc-deficient animals in the midileum. Mucosal zinc-dependent enzymes, alkaline phosphatase and leucine aminopeptidase, were likewise depressed in zinc-deficient animals. Findings suggest that zinc deficiency in short-bowel syndrome will likely impair mucosal hyperplasia. [ABSTRACT FROM AUTHOR]

Mucocele of the vermiform appendix was the term formerly used to describe all mucin-secreting lesions of the appendix. In actuality, there are three distinct clinicopathologic entities based on histologic differences. These are mucosal hyperplasia, cystadenoma, and mucinous cystadenocarcinoma of the appendix. Mucosal hyperplasia is usually an incidental finding during laparotomy for an unrelated condition. The case presented herein differed in that the patient had a three-month history of abdominal pain with nothing to suggest the presence of appendicitis, and a 3-cm opacification overlying the right iliac bone on x-ray. [ABSTRACT FROM AUTHOR]

Covered self-expandable metal stents were developed to overcome tumor in-growth through the metal mesh. Stent migration is one of their malfunctions. Recently, the partially covered wallflex stent (PCWS) was developed with flared ends to prevent migration However, difficulty has been reported in its removal. We describe the removal of a PCWS embedded in mucosal hyperplasia at the uncovered proximal flared end, visualized by using SpyGlass cholangioscopy.

Animal studies demonstrate that the resection of bypassed bowel reduces liver damage and stimulates mucosal hyperplasia in remaining intact bowel. These findings may explain the beneficial effect on liver function of jejunal loop inter-position in bypassed patients with liver disease., (© 1982 International Life Sciences Institute.)